In my (admittedly limited) experience people don't weld contacts to their eyes, nor are contacts capable of physically restraining you from pushing an 'Off' but

In my (admittedly limited) experience people don't weld contacts to their eyes, nor are contacts capable of physically restraining you from pushing an 'Off' button. I suppose you could attack someone with epilepsy this way. The rest of your post is rather more accurate. Hence the need for good security (on devices that you don't wear as well as ones that you do).