Last modified: 2013-03-19 05:21:00 UTC
It just say " Login error There is no user by the name "...". Check your spelling, or go to Wikipedia's signup page to create a new user account. " without much info about AntiSpoof.
What's in the "..."? Is it just three full stops, or is it the attempted login username?
Sorry I did the test incorrectly. Actually the conflicting user name can be created (with AntiSpoof bypassed) automatically.