In that case, what good are waivers at all if people are just gonna sue anyway?
Truth is, companies have to be very careful with waivers. For example, if it was a cake eating contest and somebody choked to death BUT there had been medical assistance available - however they couldn't help and the person died anyway - THEN the chances are the waiver would be ok because the station would've taken all the precautions necessary. The problem here is that the station DIDN'T take all the precaustions that a proper risk analysis would've highlighted, and so are negligent. It's a fine line.
A lot of the time waivers are not legally enforceable though, a lot of companies just use them to try and escape their obligations and limit their liability even though they wouldn't stand up in court. The most common one is in cloakrooms at nightclubs and restaurants etc. where they say that jackets left are at the owners risk and so they don't take any responsibility. If the cloakroom has staff manning it it doesn't matter what they say - it IS their responsibility and you CAN reclaim any loss. It's only if there is no staff that they can play that card.
There are loads of other examples - thing to remember is that in most cases, a waiver does not affect your statutory rights, it's basically a 'gentlemans agreement' if you will.