> Do you consider this feature to be a violation of your privacy, requiring an opt-in?

I suppose in some sense it is, as it a reverse-geo lookup service, but it's also no where near to the front in the location privacy war.

Cell phone providers basically know your exact position at all times when you have your phone on you, credit card companies know basically everything, cars track driving directly, etc. etc.

I can see why some people would be up in arms but for me this one doesn't feel like missing the forest for the trees, it feels like missing the forest for the leaves.