No, they're not the same thing. As the MS article states, one of the conditions required to cause this is:

"The guest user account has been deleted from the sysusers system...

Careful what you say about DELETING the guest user!  My theory is that all this was caused by the administrators manually deleting the...

Nice try, but all objects are owned by dbo.  Besides, the error occurs on querying the available databases, well before any objects start to transfer.