>though keeping it safe when such mechanisms FAIL is where it could be really tricky.

100% - oh yeah. I almost wonder if - especially if you're using it for driving that it could have a manual eject that flips the lenses out so it's impossible for it to obstruct your eyes. Imagine that shit just filled the entire thing with some crash screen or popup, my god. You want to be able to quickly and physically press a button or something. Although if they're simple glasses you could just smack em off and grab the wheel.