I am sure this has happened to you before. An AR that you need for your match that is supposed to start on-time is being held up on another field because the other field is running behind. Had that happen in a very competitive U19 match. The ladies were waiting, we gave the AR another 5 minutes but he was still centering his match and no one knew exactly how to long remained.
I recruited a parent, gave him instructions as to what to call and what not to call (call nothing, don't call basically everything). But I made one mistake that I hope to correct for the next time we encounter such a thing. I never told him how I wanted to handle the baton exchange if you will. So 5 minutes later, my AR starts running towards our field, taking off his red jersey and putting on his green jersey. As he prepares to enter the field, my AR runs over to him while the ball is in play on his side and starts trying to do the exchange. At that moment, the attacking team makes a great through ball pass to an apparently onside attacker from my perspective and puts it in the net. Defense goes ballistic.
Coach that just got scored on, to his credit, told the girls to quit yapping and just play their game since he was the one that had pushed for a stand in while the other AR made his way over to our field. The rest of the game went fine. Good match up between a skilled team and another that was just one level higher.
The lesson learned here for me was that when we are going to make the switch back to the 3 man system instead of the 2 plus club AR, is to STOP the match, make the switch and then restart. The other lesson learned is to cover the changing of the guard process to the club AR so they don't try to pull one at the exact same time that the attacking team is trying to put one in the net. But it is always an interesting thing, especially when it becomes something that you had not considered before.