The gun won't shoot until the trigger is actually pulled. other guns may shoot when the gun is dropped,the hammer falls...etc. Glocks won't shoot unless that tiny part of the trigger is pulled. If you find your finger on the trigger when you are holstering, you will hear a bang...then a certain amount of pain.
DK
ping for the fat thing.
Modern guns should definately not fire from a drop on the hammer. Not any manufactured since WWII.