Interesting these have been out for 10 months now and this is the first we've heard about it.
I first reported my use of the DX1 in Aug 2007. They've been available for a few years.

I've only changed the button arrangement a couple of times. They stay in place until twisted off to be removed.
I've been using the Logitech Trackball since it came out, long before I started playing WoW.