I didn't, my home insurance has got a seriously good accidental damage policy and it covers me for anywhere in the world, I always make sure of that so that should be enough for me.
Having said that, for the first time ever I am actually considering AppleCare+ once the watch arrives, just for the extra peace of mind and the fact that Apple will be a damn sight quicker than my insurers at sorting out a problem in the unlikely event of something happening.
Plus my plan is to skip version 2 and buy version 3 of the Watch (yeah, lets see how that goes lol) so the cover will have run out by then.