I hadn’t completely figured out who the spy was, but once revealed I wasn’t completely surprised. Once revealed I wasn’t surprised at who hired him either. That sort of subterfuge to discredit unions did happen.
I feel like with the other stuff going on towards the end of the book I wasn’t even really trying to figure out who was spying. I wasn’t totally surprised when they did reveal who the spy was or why he was hired though, it fit with with what the men in control were up to