Now that my group is set to moderate messages with attachments, I can succesfully reject messages with attachments that don't conform to our naming convention. However, that just necessitates my contacting the member offlist and asking them to rename their files and resend the whole message.
It would be infinitely (I don't use that word lightly) - infinitely more convenient, at least for my group, if I could edit the pending message by (a) removing the attachments and (b) then ADDING the correctly named attachments after renaming the files myself offlist. But for some reason, the editing panel, for either an existing or a pending message, does not allow adding attachments. You can successfully delete them. Just not add any.
I think adding the ability to add an attachment while editing a message would make things easier in many situations, not just my particular one.
Messages are the sole opinion of the author, especially the fishy ones.