> Note that it's very easy to opt out of this: turn the phone off. You click one button. I agree with you on the first part, and I really see this as no differ

> Note that it's very easy to opt out of this: turn the phone off. You click one button. I agree with you on the first part, and I really see this as no different and no worse than online visitor tracking. It's a trivial thing to worry about and I don't think people should be concerned over it. That said, though, for the folks that are, it's not always that easy to just turn off the phone. Sure, most people have their cell phones on as a convenience and it wouldn't hurt them a bit to turn it off for a few minutes while in the store, but if you have the phone on because your kids are home alone, or your ailing parent may need you at any moment, etc. it becomes much more problematic. So, in this case, while the opt-out option is simple and trivial for most people, it's practically outright unavailable, or at least perceived as unavailable, to a particular segment of the customers. Even in those instances, the cell phone is often as much or more about peace of mind than actual emergency, but I'd argue that's just as valid a reason to keep the phone on for someone in those situations.