Honestly, I don't know, I would have to do tests with some groups housed in normal, smaller caging, and other groups in very large cages with lots of air space. At the moment though, I have neither the space or the time to conduct such tests, maybe when I move I'll try it out though, we'll see!(I dislike being stuck with guest account, it can't edit posts)
Hisserdude, how likely is it that your roaches refuse to fly simply because they are confined in a cage too small, and they have accepted defeat? This is probably not the situation with my Cotinis scarab, because it never gives up when it wants to fly, and it usually stops after being fed fruit.