In Boston, using turn signals is treasonous -- you're giving information to the enemy!
Funnily enough, Ottawa drivers are a lot more tame, but they have this annoying habit of trying to block you when you want to merge. The Roadster is great for that because they don't have enough time to react.
No. When indicating a turn, that light would blink amber (instead of red). You still have the other tail light and the CHMSL to be solid red for braking.
Okay, I think it's reasonable for it to suppress the brake light and blink amber.
There is precedent for this sort of thing; I've noticed some cars now dim the headlight on one side so oncoming cars can see the turn blinker. Great for the oncoming cars... but I've always wondered whether the driver can see where he's going.