The reason I was told not to put my mask on my head was simple "if it is on top of your head it can fall off easier if a wave hits you." My mask doesn’t float. I’ve heard the panicked diver with the mask on their head or completely off...I fall back to some of the comments about the rescuer (or the wanna be a hero) assessing the situation. A calm diver talking to their buddy probably isn’t panicking.
I will be waving my arms and screaming if I need help (maybe with or without a mask). If you see me exhibiting this behavior look for pirates with guns, large dorsal fins, or a spear in my leg.
I personally leave my mask on until I am on the boat and then I take it off. I’ve actually seen a mask fly off a guys head on the way to a dive site. A faster moving boat than most I’ve been on in Hawaii, a little bumpier, and he was leaning back against the rail.
I won’t even touch the topic of what the books say about an Instructor / Divemaster and the equipment they should / should not have and how to wear or use it. Keep blowing bubbles.