Hi slinnils, welcome aboard the board, lol.
Imho, you do not detect graveyards. Many people will leave things on gravesites that sometimes wash over to the sides. They're just little trinkets and memorials, and it's a matter of respect, that you don't mess with the dead. I don't think I could detect even an old rundown abandoned one. That's just me, though.
Our family graveyard is besides a church, I could see doing around the church area, if they would let you, but I would probably go ballistic on someone, I seen them detecting and digging around my families plots (we have bout 50 people in one cemetery).
We paid for them plots, they weren't cheap, they're ours, stay off them! LOL!