No clue on Argentina, but a lot of American resorts "require" leashes, but the rule is never enforced.
As for the runaway snowboard, in all my years of riding, I've seen exactly one. Meanwhile, hardly a week goes by that some two planker wanker isn't poking and prodding around trying to find his lost ski.
"People say that marijuana smoking is going to get in the way of my career. I say to them that on the contrary, my fighting career is getting in the way of my marijuana smoking." -Nick Diaz