This didn't happen in the US, but I feel it's related enough to comment.

Last week, returning to SJU from GUA (via PTY), the Guatemalan TSA equivalents (not sure what their agency name is) took away my bar shampoo and soap I've been traveling with for some time. No explanation, nothing. She let go of the cologne I had deeper in the bag, but took away my bars of soap/shampoo stating that they were liquid (even though they were clearly solid).

I didn't bother to fight it, since I didn't (and still don't) know what power the Guatemalan TSO equivalents have.

Funny thing though, they have crappy photocopies of US TSA 3-1-1 flyers and posters at the checkpoint,