Its happened to me but the pistol had the European heel type magazine release.
EDIT: Possible conflict in terminology with the previous post. By 'heel' type mag release, I was refering to the mag release typically found in Eoropean pistols. That release is located in the base of the handle, toward the aft part of the magazine well. Push it to the rear, and the mag releases. Let the back of a chair or a seat cushion bush it to the rear, the mag still releases.