A couple of years back I was on a 5 day job over at Hanford at one of their remediation sites (got to see their dead reactor core graveyard from ships / subs - awesome) and took my S&W 40. Not thinking ahead I figured I would just leave it in the safe at the hotel off site when I was going to the job site. The thought that never occurred to me was on the last day I would be checking out, going to the job site to wrap up, then heading back west meant all my baggage would be in the van, including my pistol. I got thru the last security check with no problem but was sweating my ass off the rest of the day till I got the sign off and got off the reservation.
Lesson learned to always think ahead on things when traveling with a sidearm.