If these are uncommon enough, a Tesla could just stop on the side of the road and alert the driver. There will be a driver inside anyway. And there is a huge difference between "no L5, you have to keep an eye of the road every 10 seconds all the time", and "drives itself, but once every 2 hours, or in extreme weather conditions safely warns you and makes you take over and force you to drive yourself". This could very well be a great usecase, even if it won't drive itself for those 1% of cases.