I think this is an issue related to gaming in general, and as such while it involves politics it doesn't nessicarly belong on the politics board which exists to seperate things from gaming discussion and the like.
As far as the law goes, I think Jack Thomson is simply saying the law won't work, not that he doesn't approve or anything. He's right to be honest, because similar things have been tried with Cigarettes and the like. Most of the pressure had to be put on the people lying about their age to buy smokes rather than the merchants because it can be nearly impossible for them to accuratly tell what age someone is in this world of fake IDs and such.
A way of achieving the same effect would be to enhance the penelties and policing aimed at the consumers themselves. Basically holding kids or parents responsible for the purchuse of such games. So basically if Jr. is caught going into a store and using a fake ID to try and buy an AO or M game he can be (in theory) packed off to Juvie, or his parents could be fined. Of course even then this is pointless because you have parents buying the games for their kids anyway (as many parents buy cigarettes for their teenagers), and kids will use proxies of the proper age to make purchuses for them.
The bottom line is that it's a huge mess, as it puts unreasonable expectations on the shopkeepers and merchants (ie, can a minimum wage clerk spot a fake ID?), and there are simply too many variables.
Still I could see Jack Thomson trying to back similar policies to what they use for Alcohol or Cigarettes, simply because it's a tool. Not one that works extremely well, but still something. I disagree with it of course though.
To make a political comment though, I will point out that since it occasionally comes up, that you'll notice that again all 4 of the politicians mentioned in articles connected to this as supporting/sponsoring the law are Democrats. While the issue goes accross party lines, it's mostly a left wing one right now and that is why it has taken off so much with the current change of administration. Something to keep in mind when you vote (though stil you need to know WHO you are voting for specifically, not just the party).
Such are my thoughts/observations/opinions.