Your scooter would keep going just as if you had taken your hand off the throttle, nothing very dramatic at all - switch it back on and your on your way as if nothing has happened. 
My 400 will restart it self with out the brake -so far it has never happened to me below 40 so I can't say about slower speeds -You can turn the switch back on but I believe you would have to pull over to restart the beast. AS you know it requires you to apply a brake lever in order to start it.
When I get off work tonight I'll test this out on the 650 (There shouldn't be any traffic to worry about at 01:30).Randy said:The engine should restart without touching the brake if you accidentally hit the kill switch while riding.Just "flip" it back onl