I try to brow beat this neckbeards into respecting the tables by not putting drinks on the table but it's a losing battle.
Generally, common sense. I think in a strict sense, people aren't supposed to be eat over the tables and such. So I would err on the side of caution here.
The community encourages painted figures and I hope you have a sense of humor if you don't paint. Normal guy banter ensues if you don't paint your figs for a while. No real restrictions for casual games and tournaments but most of the megabattles are pushing for painted models only.