Billing systems for phone lines have been sophisticated and detailed for quite some time. The Telco knows exactly who is originating the call, at least for the

Billing systems for phone lines have been sophisticated and detailed for quite some time. The Telco knows exactly who is originating the call, at least for the last leg of it, and could trivially issue marks against them, till they get booted off the network. But alas, why would you boot the entity giving you 100x the revenue than the target?