I cross the US border several times a year, but naturally get the Canadian exemption to the fingerprint requirement. However, they have a long long file on me, what with all the entries, some of them under odd ticketing arrangements (long story). I get paid by university research grants that are actually just not much more than software development professional services contracts for government and business, and at least one contract required that I get a rudimentary background check presumably carried out by federal security officials. I passed, of course, but they definitely have a dossier on me.