I think the thing is, alot of things might actually set of a MAD system. So if you're just trying to con your way past a guard checkpoint, I don't think cyberware should really hinder you (unless you have other things you want to hide on your person, and need to avoid a pat down). I imagine guards are totally OK with people saying "Hey, I got a datajack."
Also, yes, sometimes I have seen stuff saying that cyberware is made of non ferrous materials that don't set of MADs, so this is on your GM. I would say it is unreasonable to turn away someone with cybernetics just due to a MAD scan. Unless once again, your goal is to actually hide any cybernetics (and appear as a normal human). Maybe its just my way of running SR in the past, but I generally think cyberware is actually kind of common (an arm here or there, eyes, ears, plenty of datajacks/internal commlinks).