The Lost Sock Mystery

No, this isn't about losing socks at the laundermat. It's about the lost socks I've been seeing around Paris lately - three in one week! Now, lost gloves I understand (see my friend Jill's lost glove site for loads of examples). But how, exactly, would one lose a sock - especially in the Paris metro? I've thought of all sorts of scenarios (most of which I can't print, since this is a family blog), but have not been able to come up with anything more plausible than this: someone did a load of laundry, brought it home on the metro (the very thought makes me tired), and a sock fell out. Later, some thoughtful passerby picked it up and hung it over the rail, hoping that the person who lost it would come back for it.

Any other ideas? I have a nice single wool/poly sock for the winner...