There are plenty of good reasons to wear gloves depending on what you’re making. For example, the heat from your hands will melt the fat and change the meat if you are preparing for smash burgers or something. But for sure, if you think they are just putting on gloves - instead of washing their hands… as a catch all - that’s not a good sign.

As far as red flags - it’s hard to tell ahead of time. I won’t eat at places where it smells like tons of cleaning fluid. I won’t return to a restaurant if the people seating me have no social skills, if I see mold, loud fans, gross carpets and furniture, food that doesn’t have fish but smells like it does… but many of those things are what you find out over the course of your first time there. Sometimes rude waiter = the best secret place.

If it’s empty - and/or the menu is too big, they probably don’t know what they are doing. Besides that… I end up having to find out…