I don't go to conventions, but what policing are you talking about? Like, people aren't allowed to go and promote games that don't fall under left-think ideology?
Its been popping up sporatically up till lockdowns pretty much put the kibosh on cons for now.
We've had cons removing events because either someone woke complained, or they got woke and nixed whatever was deemed "problematic". We've had cons flat out state certain things were now verboten. And in the early stages of this cult we saw things like seminars at cons and more. Then theres been several attempts to strongarm and in at least two cases, blackmail cons into bending knee.
Back in the 90s iteration of this I had the misfortune of being at ground zero of one of these hate groups attacks on a con that literally ended with us being policed at the con and security guards watching us in the RPG rooms. ARMED security guards. A year later they took over the con completely and booted anyone "offensive". And a year later the con was DOA.
Still my go-to example of just how bad this can get. And afterwards this group of course escalated to acts of violence and their version of cancel culture.
This is in part why I have zero tolerance for SJW cults and very little patience for anyone trying to say that it cant get "that" bad. Or that this isnt really a problem.