I wonder... before buzz, her ex-husband could also have followed her, probably without her ever noticing. Now that buzz generated, well, buzz, she found out about it and now can actually take mesures to block her ex. While I see dubious value of automatically setting often mailing addresses to following (this should not have been the case, IMHO), I have a feeling that the much more visible follow-relationships right…
You don't get to cherry-pick the scenarios. If you're going to play the cost-benefit game you have to enumerate them all, or at least all of the common ones. (Here's just one of the many alternative scenarios: For every technically-sophisticated stalker who is unmasked by this change, I'll bet there are several technically-unsophisticated stalkers who didn't used to know how to stalk someone through Google, but who n…
I do also think though that the previous setup provided security by obscurity (it was hard to stalk, but it was also hard to notice being stalked), whereas the new setup is open about that fact.
Relying on your stalker not to be technically-sophisticated seems risky.
I agree on the point of not changing existing tools, though arguably, this was a change for the better (now you see that you are being stalked and how to stop it), albeit one which could have done even better (by turning all of the existing features off, then implementing buzz and then giving people the chance to opt-in again).