It definitely is. I just made a quick, easy $920.00 for repairing one that a fireman took a 2 minute ride on during a drunken stupor at a fireman's fair last fall.
It cracked the chopper motor casting and damaged the brushes and commutators.
It has been done already, but with damage.
Supposedly, there is a video of him doing it.
Of all the things that have been posted on this board I find this the most farfetched thing I have ever read.
What "chopper motor casting" did it break? For it to break anything on the chopper motor it would have to shear off the 4 1/4-20 bolts that hold the bronze chopper stator into the chopper housing then it would have to break the casting the windings are in. There is just no way in he11 that it's going to break the bronze stator unless maybe the horn bolts might pull out. If the thing did fail to that extent I can't imagine that the thing would stay up and hold the guy. For it to damage all that the horn support and bolts and the mounting into the chopper stator would have to fail first.
Aside from breaking the siren I can't imagine any department, volunteer or otherwise, that would put a ladder up and let a drunk guy get on a horn and then turn the rotator on. This is just isn't believable. If I see the video I'll believe it.
As far as "riding a horn" goes I would think that's the biggest danger is falling off when the thing starts turning.