I don't know the answer to this specifically, but I do know that if it is just a standard luggage lock, they already have all the keys. I once read a trip report where someone who had lost a bag and was telling the airline clerk what was in the bag because it wasn't labeled w/ a name tag and they needed identifying items. After she told them she offered the key to the bag, the airline clerks response was "oh we don't need that". And she got the bag back, re-locked!