In the first couple of years after my wife became my keyholder, we used the original chastity cage I'd bought before I'd gotten the guts to share with her, the CB-6000. It's a hard plastic cage (and yes, like so many others, after extended use, the seam cracked and we replaced it).
And I can definitely relate to this caption, because the sound of the "wolfdog" metal lock on the plastic could be distinctly audible under the right (or wrong) circumstances.
I can recall numerous times being out in public, wearing something relatively loose and baggy to disguise being caged, but making this noticeable clacking sound if I walked too fast.....My wife always seemed to walk just a bit faster than normal too, occasionally admonishing me to keep up.
One occasion that still gets me hard when I think about it: We were getting ready to go out, and I was wrapping a rubber band around the lock to dampen the noise I knew I'd be making as we walked around during the night out (some light shopping, dinner, movie type thing). She made me stop, and take it off, saying she didn't remember giving me permission to do that. I protested, complaining that I'd make too much noise given all the walking we were going to be doing that night....
Now she doesn't show this side very often, so I still remember it vividly, she said, "That sounds like a personal problem. You should've thought of that before asking me to be your keyholder" -- just the tone of her voice and one-raised eyebrow she gave me ended the discussion. The rubber band idea was shelved, and I clacked my way through the evening.