> I wear them when I'm feeling sick, to reduce the range of transmission (although I just try and stay home)

I really, really wish more people would do this. If you are feeling sick and need to go out into public, put on a mask. This is doubly true especially if you need to take a plane flight. I understand that you probably can't reschedule your plane flight for a lot of reasons, but, for the love of God, if you're hacking up a lung on an airplane put on a damn mask.

Have some common courtesy.