The Bell System was not innocent of this either. They made a pretty clear dividing line between "craft" labor, and management. At Baby Bells programmers were pretty much unofficially (wink, wink, nudge, nudge) not management, until it came time to do strike assignments, then, all of as sudden, programmers are managers.
One question I have is: was this a conscious decision on the part of IBM and Bell System management, or was it something that just emerged?