Its a good question. I usually shoot at a cemetery 3 or 4 times a month as it is my favorite spot. I have also been escorted out of one cemetery by some rent a cops, but other then them , I have not had any hassles. That particular cemetery was a private one and there were rules against photography, even tho they were not posted. Just keep an eye out for that. Where I live, the private cemeteries can have a "no photography, no rubbings" policy. This was started from people complaining about photographers and others doing gravestone rubbings while they were there.
When Im at a cemetery I just respect others. I wont shoot if there is funeral going on, or if I see mourners at grave sites, I put the camera away.
I wont disturb any of the stones or anything belonging to them. I try to be really carefull and not cliimb around them, just in case one might break. I try not to get names in the shots, and some of the stones have photos embedded in them, so I try to stay away from that.
There are people who are dead against it...no pun intended... , but I also respect where I am. Kinda like nature. Just try to keep an eye out for others. Even if it means going back the next day.
Lookin forward to your pics.