Susbscription plugin usefulness to restrict users adding contacts?

I’'m using the subscription plugin configured as “Reject All” to avoid my users adding contacts to their roster. Nevertheless, I can see it is very easy to circumvent that mechanism.

I’'m trying with the Psi client o with jwChat:

  • User A sends a “subscription request” to user B.

  • The server sends a “reject subscription” to user A.

  • Surprisingly, user A appears in user’'s B roster and viceversa.

  • User B sends a “subscribed message” to allow user A receive their presence.

  • User A sends a “subscribed message” to allow user B receive their presence.

Am I missing anything ?

Thanks in advanced.