I think what Donna meant is that this woman said they cannot wear shirts with any kind of slogan on them, especially pertaining to this case.

Wear it on your trousers, Donna!

Perhaps it was just more of a warning that if someone DOES wear a shirt with slogans etc on it, then they will be arrested. SHE is not making the threat - she obviously knows this will happen!

If the point is to bring attention to the criminal, then this is a wise move. If you are arrested and go off kicking and screaming, that will deflect attention from him to you. And set an image for the other protesters.

Maybe you guys can carry signs?