I've been known to epoxy, polyurethane glue and other such methods to make sure my servos never move. Once I put a servo in a jet, it's never coming out unless there is a problem with the servo and then it's a huge project, but I have yet to have a servo come loose in any way. If I lose an airplane, I take the carnage, send it to horizon and ask them to put a new case on it/and or fix repair the servo. It comes back to me in new condition and I glue the little *******s into the next project.

I'm not willing to take any chances on this issue. Servo movement does not sound like something I'd be willing to accept FWIW.