Ive done a few buses in my time; press the button, they restart it, press the button, they restart it, press the button, etc etc, ad infinitum or until the driver jumps out, then you both run round the bus like a scene out of The Keystone Cops, he gets back in, press the button, etc. Hilarious! Hours and hours of fun! Until a pissed up skin-head passenger gets off the bus, throws your bike into the road and then I usually stop doing it.
I'm looking forward to an opportunity to disable a motorbike. The kill switch is the red button near the RH handlebar grip.