From the Model S Owner's Guide: "ALARM: If ON, the horn will sound if a door or the front or rear trunk is mechanically opened by non-standard means."
Why would someone want to turn this off? "Mechanically opened by non-standard means" sounds to me like someone is trying to pry the door open. Who wouldn't want the alarm to go off in that situation?
Just curious because it seems like an odd thing to make an option.