I’m only guessing but it would seem likely (and prudent) that the participants were made to sign waivers before attempting such a stunt.
I was thinking of that too after I posted. Still, events like this are gonna make the guy look like a complete fraud. Not that it matters because Tony Robbins already made his fortune.
Signing a waiver does not magically eliminate the prospect of a successful lawsuit. As my sister explained to me while going through law school, “You can’t sign away your rights.” Like everything after the legal profession gets done with it, the details are complex. The law may vary from state to state. Perhaps an attorney with better knowledge can explain further, but signing a waiver does not give the protected party a pass to do anything they want to someone who’s signed.