The only surefire way is to not valet park. The last time I valet parked my car, I witnessed a driver who didn't know how to drive stick drive my car anyways. She stalled it once, then after restarting the engine, revved the engine and dumped the clutch. I didn't make a big stink over it, I should have, but doing that once isn't going to cause long term damage. But no more valet parking for me.