This is a pretty bold move. It would be fun to have a basket of say 500 pre-paid phones scattered around so that folks could pick up a phone and drop it off to poision the data with a bunch of bogus stats. Except you could probably defeat that with ESID or IMEI filtering.
I am surprised that this is legal in California, there is legislation that forbids this sort of thing.
Even with the pre-paids, they'd stil be able to see where a person with one of those is going and their shopping patterns, therefore giving them exactly what they're looking for. They're tracking the movement of dots to analyze shopping patterns. If a dot is prepaid it doesn't make it a "fake" dot. What would really confuse them (maybe?) is getting as many phones on your person as possible then running around in circles.
Why they would choose to attempt to discover patterns on black friday though is beyond me - consumer behavior on that day is completely wacky and inconsistent with any other day of the year.
This makes me want to invest in a CDMA/GSM dev kit so I can spoof IMEIs and ESNs. I'd send them:
AA-BBBBBB-CCCCCC-'); DROP TABLE imei;--
EDIT: another thought would be to use a directional antenna with a high-power transmitter (should only take a few watts with a +23DB panel or something) and have a script run through IMEIs and ESNs a few hundred a second, then just wave the thing around wildly.
If you want to stop this, you have to make it not economically viable for them. Real-life tracking calls for real-life DoS.
I think the point is that you would pick up a burner at the entrance, and drop it off near the first store you enter. When you exit, you pick up a different burner that someone else picked up. That way, your actual path is not discovered.
I am surprised that this is legal in California, there is legislation that forbids this sort of thing.