Admittedly I've done it once or twice. But generally I treat legendaries like artifacts in a museum. When I catch one, I like to treat it as a trophy because it marks an achievement. Okay admittedly throwing a Master Ball at something doesn't count but they're rather special. I just don't like.. damaging them if you get the drift? I mean you're probably going "how the hell do you mistreat pixels" but its kind of just something that's grown on me over the years. Besides I already have Pokemon who can do the job equally as well and wasting another team slot just doesn't solve anything. You get legendaries at the end of the game and by then, you would of had to survive on HM slaves already. So what's the point in getting another one? :p