Curious about state parks closing.

I've been wanting to go to the beach more but I hate the ocean and really dont want to have to pay 300-400 dollars to pay for a pass to a town beach to swim in a super small area.

I recently went to mount tom state park which was exactly what I was looking for just a place to swim in a big lake and mind my own business. Of course with state parks now I have to check whether they hit capacity or not and today I tried to go and 5 minutes before I got there the beach closed and I drove an hour for no reason.

I was wondering though since most people pretty much start packing up and leaving around 5 or 6, do they actually stop you if you try to go in when the parking lot is emptying amd there are spaces available again?