Yes. In fact, the officers are told that they should do a self-test to show that the screening device is in proper working order. We've recognized that they shouldn't be doing that self-test with these devices while washing their windscreens, because the methanol in windshield wiper fluid can cause a positive result.
It's a training issue. Nothing is wrong with these devices. I'm not suggesting that the devices are wrong. It's a training issue that you have to accommodate when you are setting out the procedures for doing these tests.
We can all imagine using our windshield wiper fluid quite frequently in Canada. If the individual is being tested while that's happening and the officer doesn't take the proper precautions, if I were a consultant for defence counsel, l would certainly be inquiring about that.