Not only that, IMO it's unethical to expose someone else to your kink without their permission. If they flag you you'll have to show/explain to the TSA agent you're wearing a cage. That's not cool.
Having said that, I've worn a plastic cage with the plastic numbered lock through security a couple of times. Never a metal one, though. I no longer wear any cage through, though. I take it off right before I go through, put it in my carry-on, and then re-cage myself after I go through. My GF used to make me send photos to prove this is what I was doing, but she trusts me now.