The random breath testing programs operate in two ways. In some jurisdictions, any officer can pull over any car at any time and demand a sample on a roadside screening device. In other jurisdictions, they have established sobriety checkpoints, where every driver going through the checkpoint is subject. So for Parliament and airplanes, it's like the latter situation, where everyone goes through the testing. There's no discretion. They're still waved over at random, but everyone goes through the testing.
I would be happy with either. I'm not particularly perturbed if we give that power to the officers, because right now we give the officers the right to stop vehicles at random, both during routine patrol and also at sobriety checkpoints. I wouldn't be perturbed. But if we had to simply limit “random” to checkpoints and there's random screening and everyone going through the checkpoint, that would be a major step forward, and one that we would favour.