I am glad to hear your greenie is going well! Kinda odd a trainer would think showing in anything less than 3’6 at a rated show is a waste of time given the Pre-Green and Adequan divisions offer great mileage before asking a horse to step into the 3’6 ring. I don’t know if they can get the same experience at local shows, but obviously any mileage is good!
I’ve been working with one that one day over the summer realized there is no fence around the ring and decided to duck out. Luckily he never realized not going forward was an option and I was able to ride him through his temper tantrum, took about two rides with my trusty dressage whip and a shortened martingale. He no longer thinks leaving the ring on his own merit is a wise idea. I guess they all try it at some point, just easier to deal with at home!