They didn't advertise that all Teslas are capable of self-driving, they just say that the hardware has the capability. They're specifically speaking in computer terms, even - I wouldn't expect that buying a computer advertised as having the hardware to run <game> at 120fps would include a copy of that game.

But if it's a game-console that's advertised as being able to play a particular game very well... but it's also the only console capable of playing that particular game... and they're both made by the same company, seems a bit mean.

It's also equivalent to those high-end network switches with 48 ports that have soft-locks to disable ports on the switch until you fork-out $lots to unlock them: it's an artificial limitation.

I think the sensors are always on, in all cars. Just to gather data.