I grew up in an area with the 11+ for all, and the pass/fail thing was absolute. On the day the results came out, the last year of primary divided and those who passed could no longer associate with those who failed.
I had the unfortunate experience of being the only child from a large council estate who passed. My life became horrible. No friends at home; I was a snob. No friends at school, because I was council scum. By the time I was in year 9, I was truanting more than attending. But as the Grammar didn't have a truant problem, no action was taken (which at the time I thought was brilliant). I spent most of my schooldays hanging out in the bus station cafe with some 'colourful' characters and learnt lots of things I hope my DCs don't!! It was years later when I went back into education and went to uni. From the educational studies I have read, my situation was not unique.
Where I live as an adult, there are no grammar schools, but I could easily imagine that this is still situation in places today.