I fret about this all the time.
With over $400 worth of fish in my living room display, it's been made clear that if anyone is seen doing anything stupid, that's it. If deaths result from this stupidity, they will be paying for replacements.
Thankfully, everyone that regularly stays, drinks and resides in my home is very respectful of my concerns and my passion for my tanks, and all love watching the fish. I'm always worried that some reckless twit who's just here for the night will try and get some attention by dicking around.