I've been run out of Simpson at closing time, they close the gates so a person would have to park outside and walk in.
I was fishing the Meramec one night by the RC track and a Kirkwood park ranger came by and wanted to know what I was doing there that the area was closed. When I explained to him there were not signs, which he already knew. Finally told him I would pack up and leave and he says that it was okay, I was fishing, he hadn't made any calls so I didn't see him and he didn't see me. I guess we stayed maybe another hour and left, it was a slow night any way. This was not the 1st time we had fished there. If I recall there the areas close at 11 pm.
I was told by a Jeffco sheriff deputy that it was alright to fish the big river in House Springs that they would bother you, but you have better be fishing not just putting line in the water claiming your fishing.