It is a big problem at our house. We have a whole box full of socks that are somehow missing their matches. Those heartless sock-stealing gnomes....
I've never had a problem there.
But twice, in all the years I've been there, I've had other people's socks turn up in *my* clean laundry.
Both times, I've just returned them to the laundry point in hopes that they find their proper owner.
But I've heard many, many stories from here in the U.S. about those gnomes and the mysterious place beyond the dryer-hose where all the runaway socks meet up.