That requires someone to put in a conscious effort to manage and people are lazy when it's not their money. Also (thanks in large part to internet commenters,

That requires someone to put in a conscious effort to manage and people are lazy when it's not their money. Also (thanks in large part to internet commenters, many of whom on HN fit this archetype) people are afraid that a liability waver doesn't cover them when in reality unless there are aggravating circumstances a liability waver pretty much always caps your loss at the consult fee required to get your lawyer to tell the ambulance chaser to f off.