Adding namespace alias_for causes index resync?

[Tom Sommer]

I just added a new namespace-alias with alias_for.

Apparently this causes all mailbox indexes to be resynced? Is this 
intentional and/or is there some way to avoid this? My NFS storage 
pretty much kills its elf when hundreds of thausands of users needs to 
resync indexes :)

Thanks

-- 
Tom