Sounds like you almost need a helmet.
Kids do need helmets! My 6 year old niece is wearing her bike helmet after being hit by a huge potato last year. That HURTS!
There are always some bumps, but I've never heard of anyone being really hurt. I love the look on the faces of non-natives when they see flying vegetables!
The float pic you posted is a 'lookin' float.
Ours are 'throwin' floats! lol