^ I don’t think so and would suggest you might want to again read the entirety of my postings here.
Neither did I even imply that you thought brakes would stop the horse. In fact I wouldn’t know what you thought, though from the level you’re driving at I’d have hoped and anticipated that was never in your head. My comment re that was specifically in relation to a question from a novice and about “skidding”
On the other hand though you absolutely asserted that in your opinion you’d NEVER buy one without brakes because they’re so important for downward transitions.
I merely started by saying that the reason I don’t like brakes on 2 wheeler carriages was because with a 2 wheeler the carriage is more inclined to tip if they’re applied even slightly incorrectly. Whilst you and I may well be advanced drivers, truth is, the majority aren’t.
It’s a fact, not an opinion, to be kept at the forefront that braking on a 2 wheeler is intrinsically more likely to render the vehicle unstable and tip it. Even if you’re the most advanced driver in the world this fact remains a fact because of simple engineering.
I then expanded and presented an alternative view by explaining that a 2 wheeler carriage is ordinarily light and should (must!) be well balanced. Indeed for me personally there’s an assumption that the horse is not going to find it uncomfortable or difficult and particularly not for doing the likes of dressage on a level surface.
I also well know though that a lot of drivers who are in 2 wheelers are not advanced drivers and haven’t had lessons and the experience of correctly using a brake on the vehicle. They should be aware that far from being “essential” brakes can be intrinsically a problem for many drivers and for most they’re an unnecessary additional cost.
I’d assert again, particularly if you have a well balanced, correctly fitted and appropriately sized and weighted 2 wheel vehicle and are driving dressage on the level that they’re absolutely unnecessary and there’s no evidence at all that they would contribute to higher scores at all, ever.
Trust me I would personally NEVER use brakes on a 2 wheeler as I do on a 4 wheeler. There’s a difference for sure when it comes to how you use them say going cross country at speed through hazards and in the context of competition that’s what I presume you now mean. Pleasure driving, driven dressage for most with a 2 wheeler then brakes are an unnecessary additional expense. And believe me I could easily indulge people by telling them when they order a 2 wheel vehicle to pay me extra for brakes!
Context of my response here was to original poster’s questions and statements.
What I took from the OP was:
First vehicle purchase. Trying to find a 2nd hand vehicle. - Going to be MUCH harder and more expensive to find a 2nd hand carriage with brakes
Was recommended 2 wheeler to reduce risk of jack knifing and tip up by first instructor - who presumably knows her ability and potential for getting it right… or wrong 
Liked brakes but thought they were helpful for create drag for a forward horse. - so limited understanding and experience there.
Wondering if brakes are a “must” - they’re not.
So Mandy, I don’t know why you’ve taken what I said personally or thought it was aimed at you.
It was nothing to do with you.