Got an email notification that an unregistered Guest had posted in a subforum that does not have Guest / Post-or-Reply permissions.

I checked the ACP and confirmed that should not be possible.

Then I checked ACP / Members and, comparing timestamps from the email and registrations, it looks like they posted and then registered a minute later.

How is that possible?

Also - the account registered using a full name, not Kylec.

The forum there does indeed allow guests to post inside of it:

Oh, shoot! Thx.

I was totally looking at another similar subforum.

Sorry for wasting your time.