This would make too many false positives, for which you'd have to do in person surveillance to verify.
>You don’t think they can identify phones in bulk collection? What evidence is there of that?
It doesn't matter if a cell tower can read your IMEI. It matters if that IMEI can be associated with your real name. Have you seen anyone's location data successfully correlated with a real identity when that location data doesn't include travel to residence or place of work? If you can solve this problem, you can sell it for more money than you could fathom.