Is it a TSA lock, you could try next time you are flying to ask TSA to unlock it for you. Most airports have the oversized baggage area so they are "customer facing".

Might tell you no but worth a shot? I have a hard time believing they are not asked this multiple times a day.

Otherwise in all my travels I went to one airport that only had 1 x ray machine (for passenger screening only) so when you checked your bag you turned around and they used the TSA key to open and hand inspect every bag. You can fly there?