As you stated, it's no different from the current situation where you have peace officers using their own senses, and officers can have false positives if they pick up, through their own senses, the smell of alcohol. If you have the aid of the passive, it is a concern, absolutely, but it's a very low concern. As I mentioned earlier, the device works best when it's six inches from the driver's face. If alcohol is picked up from a passenger or some that may have been spilled, it's usually diffused quite a bit, so that when it is picked up it doesn't give a strong reading. It may pick it up, but not enough of a reading to continue the process to the approved screening device.
On October 18th, 2016. See this statement in context.