Also, Just breaking the weapon down for transport would help fool a MAD or cyberware scanner. Think of how many hundreds (thousands?!?) of people who walk through these things everyday, with god knows what in their pockets, backpacks, briefcases and/or purses.
And remember, from a corp's view: "security is only so good as it saves money. Once it costs money, security is a detrement!"
meaning, if you system is going off every time someone has a commlink, a pen and a comb (the housing, barrel, and clip to a dis-assembled gun) on their person, that line up is not going to move AT ALL! And if that line up isn't moving, the Corp isn't making money! (after all, people are stuck in a line up and not working/shopping!)
Of course, this means they have to find someplace to re-assemble their weapons in relative privacy, and so leaves them open for attack.
All in all, it depends on where and when for security. Sometimes the easiest way is the most legal way. (hello permits on disposable SINs!) And sometimes it's heavy way ("hello Mr. store clerk, don't mind my Colt Manhunter tucked into my pants, just sell me this liter of soymilk")
Go with whatever it takes to keep the game moving forward, let the sci-fi details work themselves out!