I hear tell that there are fewer and fewer places that allow them to park and at some point they need to rest, too. Although why they’re doing that on the side of the road instead of the rest area’s truck parking is not always clear to me.
I’m still at the noob stage of cruising, but I’ve already had one shore excursion that ran late. More completely, the ship was docked at an island offshore, and so all shore excursions on the mainland had to rely on a local ferry to get people between the mainland and the docking island.
My group of a dozenish folks arrived at the ferry very skoshy until its departure time. The guide had cut it close on purpose to give us some extra time doing the activity but it worked out. Whew!
Then the ferry sat, and sat and sat and … sat. About an hour later many of us 200+ people were getting nervous, but all of us were bound for the same (only) cruise ship. Finally a gaggle of 20-ish folks arrived and clambered on and away we went about 90 minutes late.
The cruise ship had already retrieved nearly all of their shore paraphernalia when we got there and pulled up the gangways after the last passenger and couple of shore crewmen were aboard then got underway ASAP.
Clearly it happens. Clearly they had a plan. But I’ve no doubt that if that gaggle had been from a private tour, the ferry would not have been delayed and they’d have spent the night on shore and needed to get themselves home somehow.

Although why they’re doing that on the side of the road instead of the rest area’s truck parking is not always clear to me.
The truck parking spot in the rest area that I used to drive by twice a day during my commute was almost always full, to the point that semis were parked on both the entrance and exit lanes. It also wasn’t uncommon to see semis on the entrance ramps of nearby exits. As you say, they gotta park somewhere to sleep.

It’s unfortunate for the stranded tourists, but they should’ve known the risks and the penalties. I expect they actually did know, but refused to believe.
And the headlines are sexier to blame the cruise line than the shady excursion organizer.
“Cut rate organizer screws up! Film at 9!”
no one specific although i wouldnt listen to it anyways but fuck these assholes on social media who say the bridge thing in MD and other bridge accidents are part the “liberal deep states plan to starve America into submission”

It’s unfortunate for the stranded tourists, but they should’ve known the risks and the penalties. I expect they actually did know, but refused to believe.
Play stupid games, win stupid prizes.

If you’re on a cruise and you miss the departure time from a shore excursion, you are SOL.
There are a whole slew of YouTube videos of people running down a quay waving and hollering at a departing cruise ship – recorded by their fellow (ex) fellow passengers.

And the headlines are sexier to blame the cruise line than the shady excursion organizer.
I’d correct them, but that ship has sailed.

There are a whole slew of YouTube videos of people running down a quay waving and hollering at a departing cruise ship – recorded by their fellow (ex) fellow passengers.
Pier runners is the name. They can be amusing, sad, or infuriating. The best videos show the ship already moving and hte pier runners incredulous reactions once the realization hits.
Part of me feels like the ship should wait for the latecomers but charge them some sort of monetary penalty… but on thinking about it, with the numbers of people on the ship vs. running after it, a fair monetary penalty would probably be more than the cost of those latecomers to make other arrangements.
How do they collect the money? Demand it at the pier? Or try to bill them later ? I can easily see the latecomers disputing any charge that appears on their credit card later.
Plus, I’m assuming the firm departure time is to ensure they arrive at the next destination by the most efficient speed possible. Sure, they could speed up, but that would probably cost a few $10k worth of extra fuel, quite a steep fine.

Plus, I’m assuming the firm departure time is to ensure they arrive at the next destination by the most efficient speed possible.
They pay money for every minute they are tied up at the pier. And other ships have booked their time at the pier and will be very cross if there’s no place to tie up.
Exactly- there’s a time by which they have to be gone or pay more than originally planned. The port needs to handle them moving out, prepping the pier/anchorage for next use, and moving in the next ship, and delays mean extra work for the onshore crews, harbor pilots, tugboats, etc.

Plus, I’m assuming the firm departure time is to ensure they arrive at the next destination by the most efficient speed possible. Sure, they could speed up, but that would probably cost a few $10k worth of extra fuel, quite a steep fine.
Maybe less than you expect. IANA ship person but we have similar problems to solve in the airline industry.
Cruise ships want to arrive and depart at certain times of day. I expect that typically they build some slack into the transit times. Which is to say that if everything is going according to plan, they’ll arrive near the destination early then dawdle a bit before docking. Or absorb at least some of their earliness by slowing their cruise speed a bit during the last couple or few hours.
So assuming the weather and routing are nominal that day, whatever pad is built into the en-route time can be consumed as a departure delay before they get trapped into doing as you suggest, speeding up & paying the significant incremental fuel cost. If for weather or sea state or route or whatever reason their enroute time is already planned to be longer than nominal, well that leaves less slack for a delayed departure.
Lotta moving parts and as passengers we see only the tip of the iceberg.

a fair monetary penalty would probably be more than the cost of those latecomers to make other arrangements.
Almost certainly true, and once you tell them what the cost to board is they may just say “Nah, I’m good, have a nice trip without me!”
Far easier to leave on time and only stay late when it’s technically the cruise line’s fault that people are late.

Part of me feels like the ship should wait for the latecomers but charge them some sort of monetary penalty…
I see an opportunity for someone to start a company whose purpose is to delay the offical excursions, and thereby delay the departure of the ship.
It would work like this. I hire a team of people to follow one of the official shore excursions organized by the cruise line. If one of the patrons of my service discovers that they will be late returning to the ship, they call me, and I notify my team. They then take steps (blocking a road, or something like that) to delay the tour they’re following. The ship can’t leave until that tour gets back. That buys my customers some extra time to return and catch the ship.
It would be a huge logistical challenge to pull off, and the cruise company wouldn’t be happy about it, but it does seem like the economic incentive exists.
Before Covid19 I used to look at the deadline to be back at the cruise ships in Copenhagen harbour. About half an hour before I would drive the taxi along the streets leading from the fashion shops in the inner Copenhagen and look for distressed passengers. I would usually see someone struggling with big bags and running as fast as they could. They would always thank me and would almost every time have Danish kroner they had not used. “Oh just keep the rest, I’m not coming back.”.
It was a nice racket, until other drivers picked it up.
I could get to the cruise ships in fifteen minutes, it would take about forty minutes to run there
[Checks which category we’re in]
@Robot_Arm:
Depending on who wins in November, a guy w a mind like yours probably could find a spot high up in the incoming administration. You’re a natural.

Before Covid19
Now that it’s (mostly) after COVID, why not return to that tactic?
The cruise ships are not back like before and, as I said, other drivers picked it up. Nowadays I go far from the cruise terminal, all the other taxis go towards the terminal and I get the normal rides.