Do all this up front, don’t worry about blowback or address that concern up front.
I’d start with the offending party as in “Wait a sec. Why are you competing for year end awards with ammies when you are a pro?”
I think the person’s answer “well what I do doesn’t count” means that either she hasn’t read the USEF rule book, or doesn’t agree with the rule.
I either way, she is asking for permission to cheat. If you don’t care, then bend over. I care, so I won’t.
The next part of the conversation goes: “I think you need to pick one of the other. You either run your business and leave the ammies to their divisions and awards, or you spend the year reestablishing your ammy status as per USEF rules.”
If she doesn’t get that you will be prepared to follow up on her cheating, then you may decide to make that clear. It’s not a threat so much as a promise. It’s actually the kind way to go. You are handling things directly and “in house”-- giving her the opportunity to save face.
If she doesn’t take that and/or “hates you” because of it, then too bad. I can’t imagine what the negative consequences to the whistle blower would be. How does someone rationalize bad-mouthing the person who simply asked another competitor not to cheat? If people want to shoot the messenger, step us and tell your side of the story.
It is unfortunate that individuals should have to police others. It’s even more unfortunate (and unbelievable) that potential revenge should keep people from standing up-- simply asking them to follow the rules.
If I could not convince the shammy to do the right thing, I would write first to the TD-- but not under the cover of anonymity. Show up and do the right thing, especially if you believe you are. I don’t see what you have to hide. If I got blown off at that level, I’d take it to the USEF. I might make it clear to the TD along the way (but not in the first letter) that the USEF will know you tried to get him/her to handle it. Again, you are doing things directly and quietly, always offering the people to correct themselves without embarrassment or extra work. It’s their decision to make things easier or tougher.
I think the ammy status is worth protecting in the long run. For those of us who would like to compete on a somewhat level playing field, it’s an issue that keeps us coming back to shows and perhaps even the sport. I see no reason to throw money, time, effort and even milage on my horse just to know that the odds were stacked against us in the first place. Maybe others will get disgusted too. Witness the baseball/steroids fiasco.
Too bad this problem as arrived at the OPs doorstep but I do think she has an opportunity.