Slide saves are ABSOLUTELY a valid and legal form of play. Obviously this technique is only applicable to modern games where a tilt warning or two occurs before a tilt. If the legs of the machine are not visibly lifted off the game floor, this is perfectly valid. That being said, I think some players take it far too much considering what's needed to alter the ball 1-2" to get onto a flipper, but that's part of the tilt risk. If operators don't wish slide saves to be used (any damage would be to non-carpeted flooring if you have some really shitty leg levelers), then they can 1.) make the tilt bob tighter 2.) use pin footies which grip the floor better and make this technique tougher