I think you are entirely correct in that assessment, that the physical layer is vulnerable ...
A different question - one I am curious about - is what can be known: Just the fact that A and B are running a transmiter -or- their identities ...
A different question - one I am curious about - is what can be known: Just the fact that A and B are running a transmiter -or- their identities ...
1) the data sent between two nodes should be encrypted. As stated by reticulum and nomad devs, the software is in beta so privacy-violating bugs are possible, but theoretically the messages and identities can't be read by an outside agent.
2) the 33cm band[1] is not, from my brief research and basic knowledge of amateur radio, in wide use outside of hobbyists. It may be that in some places you would be the only person within a large radius actually using the band, meaning your signals stand out quite a bit to an astute observer. They would be able to triangulate the location of the transmitters with some work, but again, theoretically they could not read the communications.
So there are several opsec concerns for someone who doesn't want to draw attention to themselves.