A long while back I was playing crib with a friend, and his crib board (I might be imagining things here, but I'm fairly certain) was shaded in the 118, 119, and 120 point area. This three-point zone before the "I won!" hole was a special area within which you were no longer allowed to peg a "go" point. You could peg a go into the zone, but once you were there you needed to get your winning points from some (any!) other source.
I didn't see mention of this 'no-go zone' in the rules, so is this just a common variant? Or did I managed to get my leg pulled by someone who had penciled a shaded area onto their board?