at most, use a Gummi Stone for about 1" at the tip if it hooks too hard... but unless you know how the ski is designed to perform, and unless you know whether you've done a bad job on the bevels, you shouldn't mess with dulling.
if you're on old straight skis, I suggest dulling about 2" at the tip and tail, and work from there as you need more edge smear.
The skis I've bought recently are all sharp the entire edge length. If you take your skis to a shop to be tuned it seems like most I've been to still want to dull the tips and tails.
Maybe they figure most peoples techniques aren't that good and they will be easier to ski.
A sharp edge shouldn't cause hooking, if it's hooking you most likely have something else wrong like the bindings are too far forward, or you have too much forward lean or ramp angle.