Yet another science problem with GTS/SW stories. One could say that the source of the sizechanging only affects living organics, but then the fingernails, hair, and top layer of skin shouldn't go with them, and they do. For my money the easiest way around it is a delayed reaction; they get hit by whatever it is, and it affects EVERYTHING it hits, but the effects don't sink in until sometime later. Say, when they've had time to go home and change clothes.
Still, I'll likely just ignore it when I write this.