Best practise for deleting with Thunderbird

[Stefan G. Weichinger]

As I mentioned in another thread I set up these 2 namespaces for a
couple of users:

namespace {
  inbox = yes
  location =
  prefix =
  separator = /
  type = private
}
namespace {
  location =
maildir:/home/vmail/oeffentlich:INDEXPVT=/home/vmail/public/index/%d/%u/index
  prefix = Oeffentlich/
  separator = /
  subscriptions = yes
  type = public
}

It is planned that they all will use Thunderbird (on MS Windows) to
access their mailboxes.

Now when I create a folder in the public space and try to delete it via
thunderbird I get something like:

"Renaming not supported across non-private namespaces"

As far as I found out by browsing the web this is related to Thunderbird
trying to move (=rename) the mail from the public to the private
namespace, correct?

Setting TB to immediately remove mails (tested that, this works) seems a
bit scary to me: this removes a safety layer for the users because this
would also apply to their personal maildirs.

Is there any more elegant way of solving this?

Do I have to set up some kind of ACLs?

Some kind of "public paperbin folder" ??

Pls help me to understand this better ;-)

Regards, Stefan