^^ But even with PMs how would you know the person even knows about horse care? And that the advice is indeed valid?
I'm not being negative, BTW, but instead of looking at the forums I'd much rather contact different trainers asking if they can contribute in exchange of the ad.
I don't understand what you are asking...I assume there is a screening and "get to know you" process - as any writer does when considering a resource. I have written all kinds of articles, op-eds, and technical papers, and I have looked in many places for reference sources, and part of the process is establishing credibility. IMO I think you guys are making much ado about absolutely nothing (and I may be doing the same). The post could be a scam for all I know, but if it is indeed a writer or aspiring writer seeking people to use as resources, than you seek first-hand informatin about horses where there are horse people, and forums are one of the places where they congregate.
"Professional" trainers are a resource, but no better a resource than other people that may be experienced and credible. And honestly, many "trainers" (not all) are so constricted by time that the methods they use may be the quickest, but not necessarily the best, nor the methods a person might want to employ with their own horse, which appears to be the audience the OP is targetting. The best training is slow and steady, one step at a time, and many trainers don't have the time and take shortcuts or use "quick fix" training...not necessarily their fault as their clients limit their training time and want quick results for cost reasons. Besides, in my experience and observation, at most maybe 10% of people that claim to be trainers have the knowledge, expertise, and experience, to lay claim to the title.
I'm not trying to be a PITA here - it's just that if I were the OP, I would be saying to myself "Geesh, I was only looking for some experienced horsey folks that might be able to tell me their tips and experiences, some of which I might be able to use in my book"...