In my experience as a rater for GW, the courses often try to get me to get other raters to "fill out a foursome", especially at the new courses. (One reason I try to play at really off times is to get no flak for going out alone).
I'll admit that I do play with about 3 or 4 other raters who live near me when we can. Several together can only help each see more as there is really a lot to see on the really good courses. I try to play more than once if I can and I always try to look outside the box of where my ball, today's pins, what tees I played, how I hit it, blah blah blah expose me to the course on a particular visit.
I've said before, I like to play with my wife who gives me a totally different look at the course than another 5 hcp, a 2 or a 9 playing the same tees as me, or with women in general.
As for playing with the other raters with which I play, we really form our own opinions, I don't think any of us has ever bullied anyone else along to a higher or lower number or a uniform number for a particular course.
The architects themselves with whom I've played or candidly discussed their courses (founder of this thread included) with will tell you off the board, I am not afraid to let my honest opinions be known.