Brake light repeater?

Do any of the OBD2 tools (or other options) have a way of showing you when your brake lights are on?

I've just realised that the brake lights are on on my Superb when the auto handbrake is in operation (which must hack off the following cars in stop-start traffic), but I'd like to know when they're on as the Active Cruise operates. I'm not sure if the brakes lights are coming on as car maintains speed on an undulating motorway for example.

I loathe brake lights being on when they needn't be and I'm worried that car is turning me into one of those people that I hate...