Considering I've also attended Acen in a set of Spartan armor (Halo) with the two plasma rifles, and not a single person THE ENTIRE DAY said a single thing to me. I had more interactions posing with Nabeshin then I did with security or staff. Same as Otakon, as I did a Pyramid Head costume there, with a 7 foot wooden "knife" and my rear hanging out and never had a single issue (in this same costume, I was harassed MULTIPLE times at Tekko - when it was in the Radison). Tekko is the ONLY con I've seen where peopel are harassed over it.
The fix for this is easy. Make a black and white area for what is allowed and what is not. If security sees someone violating the policy, deal with it as such.
Also, if you're bringing a loaded air soft con to an aime convention, you're not only stupid, you're kind of a prick. Personal responsibility has to come into play at some point in time...instead of having staff babysit for you, why not ask yourself, "Is this a good idea?".
I only got one thing to say about this, it's all fun and games till someone gets hurt.