I have been playing Back & Nack for 2 months & its not a rule i have heard of.! - Thanks for raising this issue, i shall be watching for this happening.:)
(sakla) If you want to play a game with an opponent of a similar level, you can define a required BKR range for a new game invitation. Then nobody with a BKR outside this range will be able to see/accept it. (Katechka) (Bütün ipuçlarını göster)