The behaviour you saw was entirely the fault of the human behind the wheel. He was more than capable of noticing that he was holding up traffic behind him and d

The behaviour you saw was entirely the fault of the human behind the wheel. He was more than capable of noticing that he was holding up traffic behind him and driving slower than average. There's no need for Tesla to add alarms or special behaviour for this situation because they don't claim to give you full automation right now. There are still some driving tasks that are the responsibility of the driver.