Shared folders wild west

[devel - Fashion Content]

I'm trying to figure out how to manage mail folders by testing out a fresh 
install and replicating the existing accounts over.

It may be the fault of the replication script, but it does seem like the 
server allows creating folders such as:

user.info.shared.Promotion and user.info.shared.sales.Sent

How do I make sure that such folders cannot be created. As it is it has 
completely broken folder namespaces.

Henrik