I had a friend (a T) tell me that he found all his clients on facebook to block them and family members. To me that sounds utterly exhausting and quite a step to take, but he says he does it.
I'm betting on the syncing thing. And maybe she didn't realize it would alert you to the adding/removal, thus didn't want to bring it up, causing unnecessary discussion. Also it's not a good convo over email/text to have, usually it's a face to face thing to apologize for.
It sucks but I really, really wouldn't jump to "spying" or generally trying to hurt your feelings.