Roller Skates, Blades, and other ways to break your arm

Well, SO is getting into roller blading (or inline skating), and I’d like to have something to trim down the ever expanding waist as well. Floating gracefully down the sidewalk and gliding through the park sounds nice…
But I’ve broken by arm before. Twice. And I really really really don’t want to break it again.

That said, are roller skates less inherently dangerous than blades? Am I more or less likely to fall over on them? I was also wondering if there’s any “strap on” dohickey that I could attach to my boots so that I wouldn’t have to roll into class… Any such thing?