is it safe to have two backed used for the same user?

[lejeczek]

hi everybody

I wonder if it is safe (and wise) to have two passw-user 
databases for the same one user.
I'm thinking,
mail to me via pam
mail to me@this.domain via ldap
whole Maildir would be essentially the same one storage 
target, I see permissions have to be mangled, available to 
write for both vmail and actual uid.

what do you think? Is it how it's done?

regards