My neighbour asked me a question today that I couldn't answer as I've simply never tried it above water. Can you put a dive helmet (like a KM) on yourself without assistance? Anyone done/do this?
Is that the question? Can you put on a hat underwater by yourself? If you can't and s*** hits the fan you better be able to or you'll die.
If you mean:
Can you put on a hat topside by yourself, my answer is:
If you can't put your hat on yourself you shouldn't be diving.
Either way yes, I've made a standby dive where my hat wasn't cammed up properly because I was running as I put it on and it flooded, I hit the free flow and breathed, pulled my neck dam back down and cammed it up properly, but I dive a 17 B, I don't think it'd be as easy with those dumb 27 style camming devices.