The tenuous definition of'match' required by some of these customers is scary, two arabic surnames beginning with Al are assumed to have a 50% match for one agency, all chinese with the surname 'Ng' are the same person according to another!
I'm sure that somewhere in military intelligence somebody understands sifting for real patterns in this. But compared to the number of people who get refused loans, get extra security at airports or listed as 'persons of interest' the next time a child is abducted - all on the basis of a 6th degree of separation.