A bigger problem IMO is that many trainers and most clients are not that good at telling when a saddle really fits. And the saddle reps are invested in claiming that they can make their saddle fit any horse. But actually, they can’t. Most brands use one style of tree for all their models, and so all the saddles from a particular brand have the same basic tree shape. Some horses will fit a particular brand, and some never will.
I’ve watched (not saying anything, MYYOB) while barn friends spend $6000 on a saddle, get it tweaked by the rep continually, and never get a good fit. In this case, I’m not sure if the trainer was getting points back from the company for “recommending” her clients as customers, but I believe several people bought the saddle in the same time period.
A trainer who believes the sales reps pitch that one brand can be made to fit any horse, will steer clients wrong whether or not trainer is getting a kickback.
And a trainer who understands saddle fit would be less likely to push one brand, as the trainer would realize that there will be long-term consequences to clients’ performance if the saddles don’t fit, and these consequences will rebound on the trainer.