I’ve never been to one but I am curious. In these scenarios in NFL stadium parking lots (per pics of the action I have seen)some people seem to practically have travelling restaurants and appear to make way more food than they can consume. Are they selling this to others or giving it away or is it more like a picnic with shared food between friends?
Usually it’s like a big picnic, you bring/prepare what you and your group intend to eat.
It’s not at all uncommon however for folks to wander around to see what other groups are cooking and it’s not uncommon to offer passersby taste of what you have cooking because, as you observed, a lot of groups go way overboard.
I suppose some people might try to sell food stuffs at a tailgate but I think that could get you in trouble and I don’t recall seeing it.
If you pass by a tailgate with people you don’t know and take some food, it’s also usually polite to offer a few bucks and stay and chat a while.
In these scenarios beer is fungible.
I had Bills season tickets once upon a time, mid 90’s when they were good. (nowadays-- sob)
We usually were anywhere from 2-3 cars up to a dozen car loads in a group that set up together in a pack. Got out the grills and coolers and went at it. A lot of the time we were in the same area and got to know a lot of the regulars around us. It’s not as random as it looks. Different parking lots were different cultures too.
A few lots were pretty ordinary, mostly people that drove up attended the game and drove out. Where the tailgating is seems to be in a few lots, like minds and all. So that’s were the activity is, and where the cameras go.
The RV lot was pretty much a marvel to see. These people set up Saturday, maybe even Friday or Thursday and have a semi permanet town set up. I’ve seen couches and tablecloths set out.
Sure, but the OP’s question was do people sell food. I’m pretty sure you can’t sell food at a tailgate without a license.
I’m pretty sure the stadium would crack down on anyone selling food without permission. They make a lot of money licensing the concessions at the stadium and they’re not going to allow unpaid competitors.
At Rich stadium there’s a little 7-11 that’s just outside the stadium property and within easy walking distance of the parking lots. Most of the year it’s just a little suburban quickie mart. But on game days it’s a gold mine. All the prices get jacked up around 100%.
Consider there are “Game Day Friends”. People you never see otherwise who have season tickets and happen to have seats near your season ticket seats. So I can see these folks staking out a section of the parking lot too. And I can further see some sort of competition on who could produce the best spread off their tailgate.
Grilled salmon and shark steaks while “those” people over there are having a few frozen burgers and and hot dogs? Absolutly played a part sometimes.
I think it was Jack Daniels that had a competition for the best tailgaters at each of the 30 stadiums, the winners got to go to the superbowl if their team was in it. I knew the guys that won for the Bills one year. I was at their party, it cost about $35 and was all you could eat and drink. In a private lot just next to the stadium grounds. They set up a massive wedding sized tent on Wednesday and started setting up for Sunday. DJ, catered food and about 30 kegs of beer. Party went until after midnight. A lot of people that didn’t even have game tickets, were only there for the party.
That’s another thing, I went to actually go and enjoy the football. I can’t understand paying all that money for a ticket and being too shitfaced to enjoy/remember it. If the weather wasn’t awful, we always grilled and ate after the games too.
Oh, it also occurs to me that the exodus of vehicles leaving a stadium parking lot heading home has to be the definition of ‘cluster fuck’. So that could be a good reason for firing up a grill in the parking lot and cooking up a meal while the great masses are leaving.
You can’t do that in Buffalo (or at least you couldn’t). The stadium required all vehicles to be off the property within an hour of the end of the game. I don’t know the reason for this rule (they let you come in the day before the game and stay the night if you were willing to pay the fee). Maybe it was due to too many post-game fights.
Go Bills! I see that Little Nemo and I have maybe perhaps been in the same place at the same time. I never knew that they kicked everybody out, we always parked in a lot off California Drive, behind the field house. And yes to answer the point, let the crows of amatures sit in traffic, we’d be 2-3 hours later.
One thing I noticed for football games versus concerts or other one off events, is that the regular football crowd knows a lot of back roads and terciary routes to dispurse quickly. Concert folks that only go to the stadium once in a blue moon only know the main roads and clog the hell out of everything.
Tailgating is probably the only thing I miss about not having a football team in SoCal. 
Even Raiders fan could be tolerable at a tailgate.
I never saw anyone expressly selling food but like others have said, if you walk up to a tailgate you should over something if you’re going to partake.