There are huge practical differences between Ireland, a small country with a population of about four and a half or five million, and Canada, a huge country. Large parts of our country have small detachments and the resources required to run full check stop programs are enormous. They're so enormous that even in large cities like Toronto, they're reserved for a few seasons of the year. If it was required that it be at a check stop, it probably would not have much effect at all.
The other thing is in Australia, a review of the random breath testing program said you can't be in the same place all the time, using the same resources, because people will drive around you, so it's essential that you be unpredictable. That's what this would be.