Everyone knows the term "set etiquette", it's how we conduct ourselves on set, especially in front of specific cast and crew. Sometimes shoots get stressful, and there's a lot of hurry up and wait, and thus, from time to time, slip ups happen; but mostly, we do our best to be on our best behavior. The overall theme is, use common sense, and do your best.
The same principles and theories should be applied to how you treat gear, especially gear that isn't yours. Your mom always told you to keep your feet off other people coffee tables, and she should have told you to respect other people very expensive gear. Irregardless of price, other people's gear should be treated better than you treat yours. It should be returned in as good of shape as you got it, and it should be returned packed up neat and organized. Sure, you're paying to rent the gear, but you're not paying to destroy or mistreat it.
This may sound like a rant, because that's what it is. We here at F11 Rentals in Las Vegas have a ton of great customers who take good care of our production rental gear. Sure, there's the occasional bad apple, but we are fortunate that most gear comes back just fine. So, if you or someone you know is a bad apple, reach out to us for help, and we'll be glad to set you on the right path.