Agree with Pete.The mask on forehead panic thing is BS. If someone is in panic it's more likely the mask will go sailing off into the depths than pushed up on the forehead. One of my favorite moments as a DM was leading a group of rescue students and DM candidates while the instructor was teaching an OW class. They were going over the dive plan on the surface in shallow water. At my signal we all began to circle them casually and listen to the briefing. At my next signal we all pushed our masks up onto our foreheads and just stood there in the water. The look he gave me was priceless. Yet not one person reacted to our "distress". So much for that myth.
Apparently the DM/C's were not idiots. Good for them.
Again, the idea is that rejecting equipment can be A sign of distress... taken along with other possible signs and indicators. I've never read or seen anyone, anywhere, suggest that MOF is universally - and singularly - an absolute binary indicator of distress. But, having seen it for myself several times, I do now pay a bit of attention to someone who surfaces and immediately shoves their mask up off their face. However, since I'm not an idiot, I take the whole picture in. If they push their mask up and begin calmly chatting with their buddy about what a great dive they just had they are obviously not in any trouble.