I had a fun one coming back from vacation this year. I carry a CPAP machine, and well, they get scanned seperately. Evidently some dried up hard water caused an issue - the part of NM I was in is well known for having some radioisotopes in the water/dust, and the humidifier must have tripped something. All sorts of tests, and then the guy goes to his supervisor, who laughed, waved me through, looked at the Jr guy and said "His first day" - kept my cool and all was good. The only reason I know it was something radioactive was overhearing the guys. I gather it was ULTRA low level