We have a couple of systems locally and Kentuck specifically with pull out the tape measure, if you're over 50" you get a ticket. It doesn't matter if you fit through the 53" gate.
I get the reasoning behind the 50" limit it's to keep a 1000 with 34" tires off the trails, reduce Maintence, keep younger kids safe by keeping the faster more popular sport machines off a set of trails. But if your 50" "CLASS machine fits through the gates they put up. That's on them if they want to restrict you to 50" physically then make it a 51" gate.