Ladies and gentlemen of the group:
We really have a policy against discussing spam or offending posts. We take appropriate measures, and don't use the group to warn people or discuss it. It just causes unnecessary discussion, and also giving attention to a spammer is EXACTLY what they want, attention.
The people who have apparently had their accounts compromised know who they are by now, and whenever in doubt, a good thing is to change your password(s).
All of this is just good "Internet" common sense.
OK, now back to trains!