I don't believe this is correct. If you want to change lanes, you engage the turn signal, Supercruise will show blue light. The blue light denotes Super cruise is paused while you change lanes. After you've changed lanes yourself, you wait for the light to glow blue again so Supercruise can resume.
Tesla will speed up or slow down and change lanes automatically. This is not the same. Also, Supercruise is only enabled in very limited circumstances. You can use autopilot anywhere even if it isn't officially recommended.
> Tesla will speed up or slow down and change lanes automatically.
You are still required to engage the turn signal; Tesla will speed up / slow down to execute the merge, eventually, and will steer the merge for you but does not make the decision to do so autonomously (though it'll recommend a new lane to you with a blue lane line on your dash).
Here is a video from Cadillac showing your statement is false: https://www.youtube.com/watch?v=_rxW68ADldI&t=0m39s
Tesla will speed up or slow down and change lanes automatically. This is not the same. Also, Supercruise is only enabled in very limited circumstances. You can use autopilot anywhere even if it isn't officially recommended.