Lol, seems like a funny coincidence, I was just rereading through the memorandum yesterday to clarify some points regarding this exact issue.
Now as much as I'd like to discuss this topic more, it seems to be a bit of a taboo topic here on ASC due to the fact that most people don't want to encourage the behavior due to the potential risk towards the sport and because of the "support your local retailer" thing (not a bad thing but prices seem outrageous sometimes... even between local stores). Anyways, I've pm'd a few people w/ some questions (hope you don't mind) and a note for OP which might help somewhat.
But it seems like the most important thing to take away from here is:
"Don't personally import airsoft in your lugguge through an airport, while its not illegal per say its not worth the hassle and potential butt prodding by customs"