The reason the owners manual says not to bump start a bike is because it stresses the drive components. If you have a weak chain and start trying to bump start it in 1st you could, in a one in a million shot, break the chain. It also wears on the transmission because it was not designed to start a high compression engine. so if you bump start your bike EVERY time you start your bike, it will do noticeable damage.
But if you do it once in a while, typically when a battery is going bad, you'll be fine.
I had to bump start mine yesterday because I was working on it and left the lights on too long. Tried to start it and all i got was clicking. So i pushed it as fast as i could run, hopped on, dropped it in 2nd, and let out on the clutch. fired right up. It was actually MUCH easier than my Buell.
make sure you guys put it in 2nd to get it to work. 1st is too tall of a gear and it will just skid the tire. 3rd will probably work too, but 2nd has never failed me.