In my experience, the these are two quite separate issues: skiing irresponsibly and skiing stoned. I can recall being with folk who were stoned and responsible, despite being stoned, and I can also recall seeing many irresponsible skiers and boarders on the hill.
For what it's worth, I've seen far more drunks that were irresponsible and reckless when past a certerain point than I have seen stoners. Folks high on pot tend to care about other people just as much if not more than when they are sober, at least the people I've come across. Folks who are blind drunk don't give a damn about anything.