I actually did just that last time I maxiglided. I was in a hurry, didn't want to wait for my hair to be bone dry, and my hair came out very smooth and silky and stayed like this for days. The trick is that the hair must not be too damp, but almost dry but not quite dry. It's hard to describe.
I didn't experience any breakage from it, and I plan to use this technique next time I flat iron again.
I'd be chicken too. Your hair has to be damn near 100% dry in my opinion before you can even think about heating it.
I like letting it airdry before I maxi it too.