The vast majority of balloon handlers are employees. Anyone with a nametag is actually an employee. Anyone without a nametag is a guest (or on very rare occasion, an employee who forgot their badge or lost it that day).
The balloon handlers themselves don't actually watch where the balloon is. Their responsibility is to hold the bones (what the ropes attach to) and follow their pilot.
The pilot (in the white jumpsuits) is responsible for safe flight of the balloon. With the height of some balloons and the close proximity of hazards, it is not always possible to avoid objects when there are wind gusts.
Chloe the clown had her arm popped this year just a few days ago but continued through the parade.
You can watch Uncle Sam having a 'catastrophic failure' at youtube.
link is here youtube.com/watch?v=wsjFkztiafk