My drums are set up so you must play Traditional grip or have a versatile matched grip. The forward tilted snare drum is the key because if they try to move it thats when I can ask them to leave if I didn't approve.
...but I don't really mind if someone wants to try out my drums. As long as the situation will allow, I don't mind someone tinkering on them. Drums increase the joy in the players, so enabling joy in others is what I aim for.