No having posted is not a reason for banning. Registration has other uses, such as having threads marked as read/new, and being able to exchange PMs.
After this latest spate of posts, I looked back at the forum settings, and much to my horror, I noted that the switch for requiring verification of emails was turn off!

I guess we missed that after the latest forum upgrade...ouch.
Anyway, I looked back at registrations and found most of the offending users. I'm sure there are a few I've missed, but I'll whittle them down quickly.
So if anyone wants to notify me about one of these posts, please include the user name (in case Mike Rawdon deletes the post before I see it--he's fast),
and give me IP address of the post as well.
Many thanks, and sorry for the inconvenience.