I'm under the impression that messages are e2e encrypted as well, not just signature usage
Discussion
The entire thing is. However, you can absolutely send encrypted content over ham bands. You cannot be sending it encrypted with the specific purpose of hiding it.
Including it into an encrypted packet doesn't make it illegal per se.
While not offering legal advice here or ever, Markqvist has a fantastic explanation here:
https://github.com/markqvist/Reticulum/issues/69#issuecomment-1167083780