The horn kill is the coolest thing about a Moby. It freaks people out when you kill it. Used to ride my old Moby to the bar and park it infront of a bunch of people hanging outside.
If you kill for for a few seconds when going along 20 mph it sounds like an air raid siren, then you switch it back on and it makes a horrendous backfire. Worth fixing as stock just for those reasons, nevermind that it tells you it's off before you pedal your ass off and it won't start.