I Really Shouldn't Laugh At This Video...
... but I can't help myself -- I just have to assume that the people who filmed it wouldn't have posted it if the kids actually got hurt.
I found this courtesy of Myron at Rontini's BBS, although he doesn't seem to have it posted on his home blog yet.
Update 0610 01 Aug: It looks like they took the video down once it went all viral... my guess is the people who made it were taking some abuse for potentially hurting their kids.
Update 2359 17 Aug: Here's the link to another copy at Google Video.