My feelings on hunting cemeteries is this.
I work for a cemetery that was founded in the early 1800's. I first went to the person that runs it and asked for written permission. At first they didn't really know what our hobby was about. So I demonstrated it to them. After a lengthy meeting I was given written permission, they even notified the local police dept. It grew into a marvelous working relationship.
Now I work for them and locate old markers / plot numbers etc. etc. that have been lost over these many decades. Many of them have been from the Spanish American and the Civil War. I have and always present them with any artifacts that have sentimental and or historical value to the cemetery. These are being prepared to be displayed in a case for all visitors to view.
In fact I have put up a website for the cemetery so those living in distant states can know that their loved ones are being cared for, and somehow feel closer to them.
It gives me a bit of inner happiness when someone has lost a sentimental article while visiting their loved ones and I am able to return it to them.
The MOST IMPORTANT thing to keep in mind is to treat the site with a deep respect for the departed.
Another side to it is that I have been asked quite often by visitors who asked me what I was doing to try to find various objects that they have lost over time at their homes. This has been from their car keys to wedding rings.
This is just my own opinion and I completely understand and respect those who feel this is not a proper place to detect.
I hope I haven't offended anyone with this post.