I don't see where she mentions anything about telling them over and over again not to use these in the tub. This type of damage shouldn't happen in just one mis-use, the toys should have been taken away as soon as damage was noted. I'm a mother of two grown children and I teach 4th grade, and children don't understand punishment that doesn't relate to the offense. I agree that this seems to take punishment to an unnecessary level.
Meanness doesn't equal punishment. I do wonder if this will turn out to be a semi-hoax on behalf of the mom, just to get her 15 seconds of internet fame.