Reading Martin Dew's statement that his B&H projector has never scratched any of his films; mine is the same. I do clean the gate before every show and often use a small nozzle on a vacuum cleaner to pick up any debris that might be lurking.
This print of 'Goldfinger' recently came up on Ebay, and all I can think of is that it's probably passed through several hands, and I wonder if any of them ever cleaned their projector. the seller, well known on Ebay, said it was from his own private collection, which would make you think you were getting something special. even in this condition it sold for £225.