as has been pointed out in other posts on this subject Swift was using the USCIS Basic Pilot Program that WatchingInAmazement posted in # 7.
therefore the real problem is where did they get all those SSNs? they are working likely with real numbers and id's.
That's a good question; where did they get all those American SSNs? I used to work in retail selling cell phones and Spanish-speaking people would come in to sign up for contracts for Verizon, Sprint, Nextel etc. Sprint was the preferred carrier for illegals since they would accept non-US ID and had a very small cash deposit. Verizon requred a SSN and wanted large deposits.
These guys would pull a scrap of paper out of their pocket with a scrawled SSN on it. If that particular SSN wasn't already in the carrier's database, it was accepted. If it took a "hit" and the SSN was already used by another customer, they would sometimes say "Wait, that's the wrong one, I have another one."