It is quite important to give the option for people to block a name in all other projects. This is important for people to be able to have a global identity. Forcing people to do this by hand is silly.
No one else can be [[User:Jimbo Wales]] in any language or project, for obvious reasons. But I am not special. Everyone deserves to be able to create and maintain a global identity.
It should be the default in all *new* cases where there is no conflict, and it should be sought (socially and peacefully) in all old cases.
--Jimbo