You're saying all this as though we can't knock them further offstage with bair or something, ICs don't have many options offstage. The only thing they can do is IC block once, then nair, fair, or air dodge which isn't great to protect them if you're bairing them further offstage.An unsafe up b would be using it when it's not safe...In other words in a situation where falco will easily intercept.
It doesn't really matter if they just 'fall'. They're going to (or should) land on the stage regardless. A bit more percent isn't a kill, so it's really just your slightly above average edgeguard. Lasers and reflectors aren't huge damage rackers. You're usage of the word, 'almost always' is the same as saying 'not all the time'. Meaning it can be a bit of luck to it. Do we really want to rely on that? Is this slightly luck based option really something that is used to sway the matchup slightly?
Reflector isn't amazing. High lag and very little damage. don't kid yourself </3
In any case, we aren't going to be getting kills from our edgeguard options on Ice Climbers unless they're at say 130+ percent for an Fsmash or something. If they're dying below that it's because they've chosen the wrong recovery method.
You wouldn't go for something just because there's a chance it won't work? The reward is very worth it, especially if it means you might gimp them and there's no risk to it. Even them, the it's very rare that it happens, this has only happened once in the many times that I've lasered an IC's side b.