Oh also, someone on IRC (I forget who, sorry) suggested this method which to my amazement works - I tried it just now. Get a plastic bag (I used a Sainsbury’s bag for life), put your hand into it, and thread the bag all the way under the wristband so you’ve got a sort of bag-glove with the wristband on the outside. Make sure the wristband isn’t twisted, then pull the bag around it and over it then off your hand again so that it pulls the wristband with it - with a bit of wriggling the wristband should come off with the bag.