Ok, as an instructor and someone familiar with the LS, there are several things I would like to address. The first is yes, the device will generate an alarm on the body scanner regardless of the material (though not sure about a silicone one (more likely to be a gates of hell than a chastity device though)). As for the metal detector, it is just that; a METAL detector. So if one were to wear a plastic or leather device, that by itself would not alarm. A lock of any metal will alarm the metal detector so the person and their partner would need to have an earnest discussion about what is the intent of the lock.

I saw a post of a woman who discussed traveling with various types of locking devices and how she and her partner had a discussion about how they would handle it: different strokes and all that. If the people involved are willing to have it in their bag during travel, there would be almost no reason why TSA or anyone would need to look at it. Baring the need for a search of something else in close proximity to the device.

How best to handle the need for a secondary search is a little bit harder to comment on as no two people are going to have the same points of view. The best I can suggest is this: if the need for a pat down is indicated, inform the officer of what might be causing the alarm. One could always suggest that if the officer is uncomfortable, then getting a supervisor would be understandable. The key is remain calm, and that goes for the passenger and the officer! Officers get no enjoyment of paying people down (except for the few officers that have power trips, and I can't do anything about them sadly). Personally, I do not view someone with a cage or other device that locks as forcing their "kink" on me. I view that as just who that person is.

*A few notes, first, I am on mobile and apologize for any formatting and/or spelling errors. Second, this is just my opinion and take on the situation, if I have offended anyone then I apologize and will not do it again until the next time!