dovecot - Oct 2013 - On mailboxes, separators, and dovecot2

While I was running dovecot 1.2.9, I had my mailboxes using the
old Courier IMAP format. i.e. my mailboxes would look like

INBOX.Orders.Scams

Going to dovecot 2 (but not 2.1), I see to have a few questions:

1) It seems I would device my mailbox thingies in 10-mail.conf:

namespace inbox {
  inbox = yes
  separator = .
  location   prefix = INBOX.
  type = private

  mailbox SPAM {
     auto=subscribe
     special_use = \Junk
  }

  mailbox Trash {
     auto=subscribe
     special_use = \Trash
  }

  mailbox Sent {
     auto=subscribe
     special_use = \Sent
  }

}

but how would I prepresent my INBOX.Orders.Scams folder? Something like

  mailbox Orders.Scams {
     auto=subscribe
  }

perhaps?

2) Reading (am I literate?) through
http://wiki2.dovecot.org/Namespaces, it seems having separator = . is
not only outdated but also a bad idea (but, I had child mailboxes as
shown above). Could anybody elaborate one that? And which clients
still do  LSUB *?