I think Mr. Justice Cory was talking about the present state of the law, not about potential changes to the law, of which this would be a potential change.
I do think—and here I'm following Professor Homel—that it is not particularly intrusive to have a breath test on top of whatever other concerns the police officer might have. It's a rather brief thing. Apparently, the person does not have to get out of the car, and it takes only a couple of minutes, so it's pressing it to say that this is a very extreme measure. It's not an extreme measure at all.
I gather this is done in New Zealand. I'm going back to New Zealand for Christmas, so I hope I get stopped in one of these stops and see exactly how they do it.
On top of that is the overwhelming concern about road safety. We highly regulate drivers. We do it because it's a very unsafe activity, as we all know. It seems to me that this is not a very intrusive measure, and it's one that the evidence suggests may well have good results.