I think it depends on the severity of the nose bleed. In this case it was in the lower portion of my nose/tons of mucous/whatever...so it was okay this time. I don't know about really large ones though.
If I ever have a giant nosebleed, I'm going to see what happens...just for the heck of it. Heh. Not that I want a large nosebleed any time in the future, though.