I think it's all a guide, they can't give you instructions for everything, post op. You just have to exercise some caution and commen sense. If it doesnt feel right, chances are it's not.
I'm using weights post op, but avoiding things like deadlifts, squats etc, as I know they will be wrong for my head. I'm swimming but only doing breaststroke, and moderate pace. This feels right to me, and is within the guidelines given to me for post op care.