Well, I'm in the US and not the UK, and here we call them blinders, but that is semantical difference and completely beside the point.
In my experience as a tank in all my time playing, the number of times that this would have been useful like this has been so small that the issue of effectively being able to use it makes it a pointless skill to have. Also, I don't have those 'blinkers/blinders/things that cover a horse's eyes' for end game raiding since I don't end game raid. I haven't even set a foot into Alex Savage yet and I'm not really planning on it in the near future, so you're wrong I that assumption there. But hey, we all make mistakes...