Why doesn't this have the same legal issues as Kinder Eggs? Maybe the watch in bottled water also can't be sold in the US? http://en.wikipedia.org/wiki/Kinder_Surprise
1. This isn't US, so those rules don't apply ("a confectionery product with a non-nutritive object, partially or totally imbedded within it, cannot be sold within the United States")
2. This may be more a viral thing than an actual packaging.
3. The water may not really be meant to be drunk, it's just a gimmick.