Because of problems like this https://meta.wikimedia.org/w/index.php?title=Talk:Title_blacklist&oldid=3192814#Fakes_of_Wikimedia_Deutschland_.28WMDE.29_staff it would be good, if user names listed on the title blacklist could still be auto created if there is a valid global account. In my opinion, that shouldn't apply to all rules, but only to some specifically marked ones (maybe with allowautocreate or smth. like that).
See also: T38939: User name blacklist should be managed globally to avoid SUL fragmentation