See, I tend to disagree. I don't actually see this as stopping anyway. 1. any serial number will be ripped or ground off. 2. Let us be honest, if I am a junk yard, and someone rolls up with 15 cats.. I know what happened. I just choose to look the other way.
This is one of those cases of "trying" to make people feel safe. Won't stop anything.
If you really wanted to make it effective, go after the root source. Go after auto junk yards or other metal buyers. It is illegal to buy stolen property, or even property a reasonable person would suspect was illegal.
So, increase the fines and go make some big news busts. Scare the **** out of the yards to stop buying truck loads of cats from people in ****ty vans. Come on.. you can tell whats legit or not.