The reality is that if your were presenting as a female, and your breast forms were made mostly of any modern explosive, it would be more than enough to take the plane down. Another threat is a GF who has had surgery, her forms could do the same thing, and there are a lot more of them. They have the sniffers all over the place etc, so like has been mentioned, the TSA agent is caught between keeping everyone safe and being sensitive to a wide list of general population needs. I'll bet he/she sees dozens of cross dressers a month.
