If Mr. Roberts was licensed to carry a weapon into the cockpit, the TSO would simply let him enter the sterile area with absolutely no checks, something which I and many others on this forum have noticed (and have no problem with, except for those who don't like the idea of fire arms in the cockpit ... not me).

So why should the rules apply to pilots who don't guns?

Anyway, every pilot should get a license to carry a gun in the cockpit, even if they don't actually bring one.