I've had some feedback from a person I know through g+ about the Location Sharing feature that was recently added to Google Maps. She receives requests from people but would like to opt out of the feature. I had a look at Maps on desktop and the App and I can't see any way for someone to not see the locations of others if they are sharing with them.
It's probably not feasible to stop the person sharing but it might be possible to offer an option to not see people who have shared their location with them.