[prawn]

Could work well for headphones? Definitely something people would be keen to try with their own equipment and music.

[cbhl]

I'd have health concerns about that; what if someone has an ear infection and then returns a pair?

[prawn]

Either they'd be cleaning them (and cameras) too or might you have similar issues of cleanliness there?

[cbhl]

I have no problems with sharing a camera though -- I have bacteria on my hands all the time from handshakes; etc., and well-established mitigating practices (washing my hands).

I suppose you could clean the headphones with rubbing alcohol...