3. If Mr.A and Mr.B have friendly chat, and end
up with,
* Mr.B willing to let Mr.A get global account of user123, since
Mr.A really want to use many wikis than Mr.B
* Mr.B willing to continue using his local user123 account (by not
changing account name)
* Mr.A also willing to let Mr.B continue to use local user123
account (by not changing Mr.B account name).
* How can Mr.A and Mr.B do, to meet this?
Easy, Mr.A and Mr.B should both become MediaWiki developers, and write the
relevant code by pair-programming.