Sidereins- Agree or Disagree?
Like most equipment in the horse world, sidereins are a tool that can be useful in very specific situations with a well prepared horse when used by someone who knows exactly what they're doing.
However, the way the vast majority of the horse world uses sidereins is something I don't condone. I can think of very few instances where I've seen them used properly, and always by masterful riders with tact, sensitivity, and decades of experience in classical dressage. And even then it's usually a transitional thing. Like you use them for a few sessions to teach the horse one very specific thing and that's it, you take them off and let them collect dust in the tack room again. Certainly not a tool you slap on every horse as a matter of course!
They do more harm then good. Most people who use them are just teaching their horses that the bit will cause pain and to contract to avoid it. There is nothing that sidereins do that cannot be done by the hand, and at far less risk to both your horses mouth and to his trust in you.