Recently I've been seeing an increasingly negative mentality towards R+/treat training, specifically when in relation to tricks. People try or someone they know tries to train their horse to do tricks or other behaviours with little research or prior knowledge, and end up with a disrespectful and sometimes even dangerous horse. Immediately they proclaim "trick training/R+/positive horsemanship is awful! Look how horribly behaved my horse is! It couldn't possibly be me, it must of course be the treats!! Perhaps it's these positive methods! I can only get respect if I smack my horse about!!"
In order to disprove this, I ask you to carry out an experiment for me. Go get a peppermint. Unwrap it. Set it on the table. Now command it to teach your horse bad habits. What? You mean it doesn't leap up and go to work? Of course it doesn't. The treats are not the issue. Reward is not the issue. Positivity is not the issue. A "trainer" who is poorly educated is. Treats/R+ simply amplify whatever you're teaching by making the correct answer more pleasant. If you're inadvertently rewarding poor behavior, you're going to get MORE bad behavior. If you only reward precisely what you want, you will weed out the bad behavior and amplify the good behavior.
Finally, I've included a few examples above. Obviously you all know myself an Sid. You can find the video of that trick on this account (as well as others). He maintains a respectful distance from my person, and when he does enter it is gently and with a pleasant attitude to retrieve the treat. On the right is perhaps the best example. This is Dawn Wescott with Monsier Chapeau. Monsier, the pony, was brought in unhandled off the moor. He has only ever been trained with positive horsemanship (not treats, but no punishment/aversive aids). Recently he completed his pony inspection entirely at liberty, and was told he "Raised the bar for inspections" by EPS inspector Colin Girdler.
The moral of the story is this: treats, tricks, and positive horsemanship aren't the problem. The problem is uneducated trainers refusing to address their own shortcomings and preferring to blame their failure on the tools they employ.