Like the people (sheeple/cattle) on MUP's around here, it wouldn't matter what they were riding or how big of a flag they had (mind you the chance of maybe seeing it beforehand would be nice) but their inconcideration is the problem. I've been on MUP's that were lined, just like a road, yet it was apparently too obvious for most users to figure out that they simply operate on it the same way they do on a road. The nice thing about a bent, is that anyone doing anything foolish in front of me is likely going to be the worse for wear. I use flags on everything except my current high racer becuase I just haven't gotten around to putting the mount on yet, but it goes on first thing in the spring (I'm on rollers with it right now - don't need the flag). I see a lot of bent riders who say it causes too much drag, or it looks lame. For me though, any extra drag just makes me stronger - more fit, and looking lame is fine with me as I think I'd likely look more lame eating a grill or radiator.