Saw the blind spot mirror flashing on a Volvo XC90 that was sat alongside me on the motorway. Simple but effective.
I have it on mine, and it is really useful, but I wonder if it slowly gets drivers to pull out without looking over their shoulder, relying on the technology?
I find the passenger side particularly useful for overtaking on the motorway, to see when safe to indicate to get back in a lane - as soon as the light goes out, I can indicate, then move.
As an ex biker, always on the lookout that other drivers have seen me, even when in the car. However, despite many E/S class Mercs having the feature, their drivers ignore it. The amount of gravel rash my car has when I've been at (almost
motorway speeds, and I've seen their little red triangle come on, and I think they must be aware I'm there so keep the boot down, only for them to pull out, leaving me with the gravel and shit near the centrral barrier as my bit of road