A family plot on private land and you have permission from the family? I say do it.
I don?t think there is anything inherently disrespectful about detecting. In regards to the act itself, If it?s not disrespectful to dig an entire new grave next to an old one, why would it be disrespectful to dig a coin 6 just inches down? In my opinion, the sensitivity to respectfulness comes from a cemetery being a place of shared community. Probably most people wouldn?t be pleased to see someone digging in the dirt around their mom?s grave. However, as detectorists, most of our mom?s probably wouldn?t care if their son was digging in the dirt around their plot,
With the blessing of the family, I think you are good to go. None the less, if the night after you are awoken by a voice saying ?give me back my golden arm? then you F?d up......