I put mine on my forehead all the time. As you say, if I lose it, my fault.I put my mask on my forehead all the time on the surface. It's my mask, my fault if I lose it.
If someone knocks it off purposely to try and prove a point, they're going to get it. If they refuse, they're going with me to get it, their ability to maintain a viable air source is of no consequence to me.
It's common courtesy, don't touch other people ****. Don't be surprised at the outcome if you do. The ONLY time I've ever been in a situation where the status quo changes is when a shop says, "if you're renting one of our masks, it goes around your neck." Their mask, their rules, and I've only been in that situation once, and happily complied. If a boat politely asks, I'm more than happy to oblige, but if someone gets douchey about it, I don't dive with them again.
Quite often with shore entries I need the visibility down at my feet to see the rocks while still in the water (mask has black skirt so absolutely no peripheral vision). Tripping at that point is a bigger hazard to me than my mask. Putting it round my neck makes it harder to angle my head down especially with the drysuit neck & hood already fairly tight around there. Taking it off and putting it on my wrist means it is a pain to re-don if needed.
Anyone throws my gear away they or their gear are following it. No if's buts or maybes.
If diving with rental gear, fair enough to stick to their rules or pay for the replacement.
I've never put my mask anywhere but on my face or my bag on the boat. I just can't think of a situation where I would be in the ocean and remove my mask with x number of feet of water below me... In the pool practicing skills I totally get it as there's little concern for losing your mask and it's easier to have a conversation without it on.
Nevertheless, MOF as a sign of distress... Maybe, odds are there are going to be better indicators. I imagine very few of us will ever see a diver truly in distress except maybe on YouTube, like this one for example... Look at where her mask ends up.
Do pool dives count for?
If I see a diver waving their arms, shouting, looking like they are struggling to maintain buoyancy or a combo of them, I might think they are in distress. I certainly will not be looking at their mask.
The whole thing about being in distress or panicked is that you will more than likely do the unexpected - if we follow the logic of MOF as a sign of distress, she was fine!