We are a 65 limit here in Ontario. Not that I've ever heard of anyone checking. Like you say it can just be too much trouble. Some places you could technically get a 72 through. But man it would be a pian in the ass. Even my 60" Sport is far simpler to get through many places, turns sharper too.you can always use binders and ratchet your wheels towards each other to narrow the car to fit in the trailer.
but yeah, 64 vs 72 is really a matter of where you ride.
I wanted a 72 but realised I would be in trouble 50% of the time, max width here is 64. and it gets enforced a lot by patrol. especial winter when trails are narrow. and also concrete block or metal fencing at a lot of places set at 66 inches.
i bought a 64, installed 5+2 rims resulting 66 ''wide car.
then raised it at 16 inches and it made it 65 '' wide.