Only major airports with international departures require a Homeland Security/Customs seal to be afixed to employees airport ID. This seal can only be obtained after the employee passes a 10 year background check that is conducted by Homeland Security. This background check is more complete then the check conducted by airlines upon employment. Airline employment check is completed when the employee is hired and that is it. The seal obtained from Customs is conducted every two years and serves as a continued background check that follows the employee thru-out their career. This background check is not conducted at airports that dont have international flights. However all airports feed international freight and baggage to major airports and this baggage continues on to connecting flights without any further TSA checks. TSA checks baggage at airports then hands baggage off to personnel at airports that dont conduct these background checks. All personnel who work inside airports and around aircraft should have this seal afixed to their ID.