High resolution tracking through cell phones

It appears that a company is now selling a tool that will allow high resolution tracking of the motion of customers through stores and malls by triangulating on their cell phones. The technique involves tracking the phone through its globally unique IMEI number. The company claims that this is anonymous because only the phone company knows the correspondence between the IMEI and the customer's real name.I have very little faith in that protection. There are simply too many ways one might extract that kind of information, which could then become widely available. One could even connect the location information and IMEI data to checkout records. After a couple of trips, it would be fairly unambiguous. This is certainly clever, but disturbing. There is no opt-in or opt-out, and the tracking takes place passively with no ability for the user to detect that it is going on.Shops track customers via mobile phone - Times Online