I think a player should get a message that says someone has tried to start a game with them but has fallen foul of some ratings restriction or maximum number of games etc. Then the challenged player has the option of accepting the kind of game that they did not actually intend to block with their settings. For example: I lose a game (as I so often do) but when I try to set up a rematch I am blocked ~ and the opponent has no way of knowing I attempted to start a rematch, unless I send a personal message. That message - that a game was offered but blocked by settings - should be automatically generated.