The caller ID is typically only added by the phone companies on pots lines. Digital lines are programmed by the source. It's how you can have 50 lines behind a PBX display different phone numbers with the majority displaying the company main number. VoIP functions largely the same because the gateway uses the same principle except the VoIPmodem or computer transmits account id numbers as well.
Yes, the phone companies know who to charge because the pri id number is associated with the calls but that is not passed on to the receiver. That also qualifies as your "paying enough money to be peering " comment except for large bundles of lines it is actually cheaper.
Just because your mom got charged for all those 1-900 sex calls doesn't mean you know what you're talking about.