Vikings: Some would consider it bad manners, but it's nice to have an official opinion for future clarification of such points as may or may not occur in the near or distant future.
(hide) 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) (show all tips)