bumping
n.β Β«This security consultant is about to demonstrate how easy it is to pop open a P.O. Box with nothing more than a tapping device and a blank key.…Itβs a method called “bumping” and he says anyone can do it. He wouldnβt let us video tape him bumping a lock at U-S Post Office Box, but said he achieved the same success.…Tobias says bumping keys are sold commercially and on the internet.Β» ββBumping P.O. Boxes” by Don Jorgensen KELO-TV (Sioux Falls, S.D.) Apr. 4, 2006. (source: Double-Tongued Dictionary)