They stripped back the ability to see a lot of things with TV, so you have to be a lot more careful at night as you won't get any kind of warning if you miss something in your vision (it can't see pedestrians or oncoming traffic for example, and in the dark can't see parked cars at all.. I've been sat in the middle of a car park at night surrounded by people and cars and TV showing clear in all directions) .
But I've never had it actually fail to switch on. I think because the motorways here are very well lit. I don't *trust* it.. the trust is gone.. but it does appear to work.