Complete garbage about law enforcement challenges!
Having listened to the crap about enforced roaming mean it will be more difficult to track criminal activity all I can say is what a load of horse poo! It's all about the mobile networks not wanting to spend money modifying their software! You can't get on without an IMEI so EVERY network tracks it. The networks will know who the roaming IMEI belongs to (network wise, not customer) and Bill accordingly.
They want their cheapest, easiest, will have an ulterior motive option which is to chuck more masts up. Not spots can also use telegraph pole or tree shaped antennas. It's not technically difficult, just not what they want to do. These Telcos are as bad as BT in their forward thinking.