—but certainly the odour is not the only thing that is used in forming reasonable suspicion to demand a screening device. I've heard enough trials to know that. This wouldn't be much different from that, but it adds another layer.
I should comment at this point that something I've been mulling over is that if the officer smells what they think is alcohol and they pull out their passive detection device, and, owing to circumstances beyond their control, it doesn't register alcohol, I think it offers a very interesting litigable point as to which side should be believed.