There actually is a problem with the technology in this case. It sounds like what they’re proposing is eye tracking, which is not reliable with some eye shapes, eye makeup, dry eye, etc. and any markers they use to try to detect drunkenness would also trip for people with legitimate eye problems. Anecdotally, I once drove a Tesla and it locked me out of cruise control because the tracker thought I was falling asleep. Imagine if the car refused to start at all!