Really? I’ve been through the checkpoint on the I-15 maybe a couple of dozen times in the few years I’ve lived here, and I have yet to see it open… I always wonder about that when I pass though.
Bryan Ekers, it’s not that they’re terrorists; it’s that they’re Canadian terrorists! That’s the worst kind… they’ll apologize as they’re cutting off your head. 
I’ve been through customs on the US/Canada border about 8 times, in 4 different places. All of the experiences but one were relatively painless (once we had to leave the car so the Canadian side could have dogs sniff our car, but that doesn’t count).
The worst was coming back into the US on the Washington border after a day trip. This guy had the WORST attitude ever. We were trying very hard to be cooperative (had birth certificates ready and everything (this is before you needed passports), but he would ask vague questions… For example “Where are you from?” We answered “Michigan” as that is our home state. He says “Awful long drive for one day.” ??? We were staying in Seattle, which is apparently the information he was looking for, but not the actual answer to the question asked.
No, we don’t look like terrorists. This guy made me very wary about going thru customs later, when we took a shortcut through Canada to New York, but there were no issues at all during any of those checks, and half the time it took less time to go through customs than to pay a toll.
Remind me again what terrorists look like. So I can spot them in the future.
I think the examples in the OP are anomalies. We’ve got pretty good reciprocal agreements in place and no reason to think this is the start of some master plan to subvert assisting each other. We’re even talking now about “smart” drivers’ licenses as passport alternatives.
Generally, they carry sniper rifles and wear ski masks. The reason there have been so few terrorist attacks on American soil, of course, is that they really stick out in (say) the mall or a sports stadium. Unfortunately, our culture’s backlash against weapon profiling is making it harder to give law enforcement The Tools To Protect America.
That describes the RCMP officer who was visiting my neighbour recently (a neoprene paddling mask rather than a ski mask, though). I had no idea that he was a police sniper, so when he was unpacking his truck, I had assumed that his rifle was for hunting, and I asked him what he liked to shoot.
It took a while for me to remove my own foot from my mouth.
Please tell me that he answered “people”.
One time about ten years ago I was crossing the border into Canada with a couple of friends. The agent asked where we lived and we all told him: West Virginia, USA, and we are coming to spend a few days at Niagara Falls.
“So, you guys must work in Buffalo, then?” he asked. We told him “No”, vacation, live in West Virginia, college students, pleasure, Niagara Falls, drinking and debauchery.
“Yeah, that’s a hard working town there, Buffalo, so where do you work there?”
After about three of those I was beginning to think this guy was dense, but it took a couple of days for the real reason (at least I think) to set in.
I think that if we were smuggling drugs into the country, his friendly attitude and ready made excuse “we work in Buffalo” would make some nervous college guys agree with him when we already said we were from WV on vacation and he would have nailed us… I think.
He didn’t say a word – it was a very awkward moment. His friend whom he was visiting (ww kayaking in late October, thus the masks) explained to me that he was an RCMP sniper, and the conversation then turned to what type of gun, what distance for accuracy, etc.
It led to another interesting conversation a few days later, when his friend said that he hopes Canadian customs/immigration officers are not issued guns, for his wife is a customs/immigration officer, and he doesn’t like the idea of his wife having such opportunity to shoot him. 
As a little girl in the early 30s, my mother entered a talent contest in Calais, Maine, where she won a live bunny for roller-skating about a stage with a water-filled glass balanced on her forehead.
When crossing back into St. Stephen, Canada, the customs office made her give up her prize.
That stuck in her craw for decades, and she always wondered if the customs officer ate her newly-won pet.