Hello Josef,
Yes, there is activity there at night, although it isn't allowed. Some like the romantic aspect in the evening, and some just a party I guess, but I wouldn't think it would be dangerous to be there. You'll get fined if the rangers catch you, though, and they do come down at night fairly often.
Please don't bring any glass.
It is only less naked when the weather is too cold, but even then a lot of the soaking is done nude.
Yep, the water is fine for drinking...just get it out of the little copper pipe at the crab cooker and it comes straight from the source. It's like Arrowhead water, only hot.
Hope you enjoy your next visit. Peace.