I should mention it wasn't actually people from the trial who's kids were the trouble makers. It was the soccer complex that chose to hold a kids party there at the same time as an agility trial. I will not enter a green dog there again. She was not the only one who had trouble because of the kids party.
Lark is a dog who doesn't handle failure. When something goes wrong, her default behavior is to quit, or shut down. At the time she was a puppy, I did not know to teach her the things I now teach my puppies. They learn to fail early on, and to keep trying and fight for what they want. I apparently have a hole that I need to go back and fix.
This might help to describe learning to fail:
http://susangarrettdogagility.com/2010/07/planning-to-fail/
Shaping... I am working on getting her to offer behaviors. I am using it and a clicker to help build the responses I want from her. It'll also help her learn to fail.
I have a plan. I am shaping away from agility right now.. fun, easy things to start with, and will progress to more difficult things. I want to isolate what the problems are, and shape a better response. Teach her to deal with what bothers her in small pieces she can handle. So problems (besides failure) are noise, people, and trials. We'll work on noise and people away from agility. Build up a better response. Then take it on the road. Go to trials, work on shaping the better response there, far away from the ring. Build up to where we can work behaviors around the ring. Build up to where we do the practice jump with a happy, unworried attitude. Shape a good response at the jump with people near it, then in the practice ring. Re-enter a class. Then build back up to doing low key fun matches. Then hopefully come back to agility trials.
Just to eliminate the possibility, I'm going to have her thyroid retested. I tested it at 18 months, but she is now 4, and would like to be sure that it isn't where some of the strange attitude has come from.