I'd argue the line gets drawn when the driver is barred from stopping the distracting element themselves. Everything else can be stopped, disabled,refused, or removed by the driver. If an element is designed to be another source for focus (the entire infotainment system is this) it must be able to be turned off by the driver. In theory simply disabling the infotainment system should cover this, but now you have to argue if removing things like modern navigation is an acceptable option, and frankly, these ads only serve to line pockets. This isn't a radio situation where the feed is free, the car is (in theory) already paid for. (and don't try to argue that the car is cheaper because of the ads. TV manufacturers already turned that argument into swiss cheese when they stopped bothering to sell TVs without preloaded ads.)