I would also post this on the MD thread to see if any MD residents had flown out of BWI.
I flew from Norfolk to Denver and back using a Pelican case and the same abloy locks without incident.
The two concerns you need to have are 1) if you get stopped anywhere in MD and the officer decides to confiscate your gun and throw you in the pokey until you can prove it isn't stolen and your destination was a legal place to bring it. 2) checking it in at the airport without the swat team surrounding you. :-)
I would think (in my opinion) that the #2 would be the safer part since TSA is under federal rules. Read up on some of the threads about "not" talking to the police and what not to say.
Good luck and let us know how it goes.