Given the bouncing if sent via email, I feel even more strongly that owner messages without a subject should be allowed. These are potentially coming from people completely unfamiliar with the group or even groups.io.
However, I agree that the issue of hashtags qualifying as subjects in group messages needs to be fixed. -- J
Messages are the sole opinion of the author, especially the fishy ones. My humanity is bound up in yours, for we can only be human together. - Desmond Tutu