In fact this can be a
tactical play by a player for the first match to be resolved.
The major reason i have added 4 cards to game, game should have come with at least 2 more cards. There are already to many goals, and all but making a guarantee goal becomes an unrealistic advantage to the teams playing in the first game and particularly to the team playing first.
In regards to discarding, yes it can be done at any time at any stage of game.