Maybe just refuse to try to help them? Why can't we let people win darwin awards anymore instead of criminalizing it? The people doing this are adrenaline junkies who often would LOVE to die this way if they had to. That's why they are doing it.
For similar reasons, suicide should not be criminalized. Yes I am serious.
If they're doing it anyway, then why bother making it legal? Just to attract more people who might otherwise be dissuaded?