What is the appropriate action if a coach enters the field without permission?

When a coach enters the field without permission, the appropriate course of action is to send the coach off the field and issue a warning. This is primarily a matter of maintaining control of the game and ensuring that the integrity of the match is upheld. The referee has the authority to enforce rules regarding coach behavior, and allowing a coach to enter the field without permission disrupts the flow of the game and could potentially lead to further issues.

Issuing a warning rather than a card is appropriate in this case, as it allows the referee to address the infraction without escalating the situation to a more severe punishment. By removing the coach from the field, the referee can help to maintain the order of the match and keep the focus on the players. This action provides a clear message that any unauthorized intrusion onto the field will not be tolerated.

In contrast, stopping the game until the coach leaves disrupts the flow more than necessary, and allowing the coach to stay could set a precedent that disregards the rules. Therefore, the response of sending the coach off and issuing a warning is a balanced approach that preserves the authority of the referee and the discipline required on the field.