GOAL SCORED WITH TOO MANY PLAYERS ON THE FIELD

Question:
My son’s U11 Soccer game STARTED with the opposing team playing with 1 additional player than my sons team team. This additional player was not detected by anyone, including the referee, his 2 assistant referees, or our coach. The opposing team scored one goal prior to the additional player being detected by one of the parents of my sons team. After detection of the additional player, 6+minutes into the match, play was stopped after the ball went out of bounds. The additional player was brought to the attention of, and verified by, the referee. The referee instructed the opposing teams coach to remove one of his players and play resumed. The final score of the match was 3-2, my son’s team lost.
I know there are rules/laws covering playing with additional players? Are there any laws governing STARTING a match with additional players?
Is there responsibility assigned to anyone to count the number of players prior to starting a match?
Isn’t it the responsibility of the coach to know the laws/rules of the game, including the legal number of players to play?

Thank You for your consideration

USSF answer (May 1, 2011):
Common sense dictates that the referee count the number of players on each time after every substitution and prior to the kick-off. That answers part of your question. The rest of your answer will be found in the USSF publication “Advice to Referees on the Laws of the Game”:

3.20 GOAL SCORED WITH EXTRA PLAYER IN THE GAME
There are two critical questions to be answered in determining the proper response to the presence of an extra person on the field following the scoring of a goal:
• Was the presence of the extra person discovered before the kick-off restart or only afterward?
• Who is the extra person – a player ordered off who returned illegally, a substitute or substituted player who entered illegally, or someone else (team official, spectator, red-carded player, etc.) referred to generally as an “outside agent”?

(a) Extra person discovered after the restart
If, after play is restarted with a kick-off and, during a subsequent stoppage, the extra person is discovered, the goal counts and play is restarted based on the reason for the current stoppage. If, however, play is stopped after the kick-off solely because the referee has become aware of the presence of an extra person, the goal stands and the game is restarted in accordance with the Law:
• an indirect free kick where the ball was when play was stopped if the extra person was either a substitute (or substituted player) or a player off the field with the referee’s permission or at the order of the referee (e.g., for an equipment or bleeding problem).
• a dropped ball where the ball was when play was stopped if the person is an outside agent or a red-carded player.

(b) Extra person discovered before play restarts.
The referee must disallow the goal if the intruder was:
• a player, substitute (or substituted player), or a team official of the team that scored the goal, or
• an outside agent who interfered with play or a player.

The referee must allow the goal if the intruder was:
• a player, substitute (or substituted player), or a team official of the team scored against, or
• an outside agent who did not interfere with play or a player.

If the goal is disallowed, the restart is a goal kick.

In all cases, the intruder must be removed from the field and cautioned if the person is a player or anyone else over whom the referee has authority. Team officials should be informed that their action was ill-advised and, if appropriate, they should be expelled from the field and its surrounds for irresponsible behavior. The match may be suspended and, if necessary, terminated where outside agents are invading the field.