Natural Horsemanship: Can you train an old horse natural horsemanship techniques?

My name is Nicola and I live in New Zealand. I have always been very interested in horses, however I have never really had the chance to learn properly. My friend was recently offered a 13 year old quarterhorse, at which she jumped at the chance. However she likes to think of herself as an experienced and knowledgeable rider ( she is just as novice as I am) and is a firm believer in going bitless and bareback.
Is it actually possible for someone of her level to train a horse of this age in the natural techniques such as going bitless? I am worried that one day she will hurt herself or others as she has too much confidence in her abilities (or lack of)
I have always respected all forms of riding, believing their is nothing wrong with using a bit or not. But despite what tools/aids you use, it still takes a professional trainer to actually train a horse properly in any sort of riding dicipline, whether it be tradtional english or natural horsemanship.
I am very interested in learning more about horses so any advice would be appreciated. :)

Imo ride the horse how it was trained to be ridden.

Do you mind explaining why you think going 'bitless' is a 'Natural technique'? What is you definition of 'Natural Horsemanship and Natural Training'?

Green + Green = Black and Blue

In this situation, a green rider to a horse green to the technique.

It's sort of hard to explain the situation. My friend (we'll call her Bec) refers to riding without a bit/saddle or sometimes any tack apart from a rope as natural horsemanship so that I just sort of took the term from her.

She's very outright in her view of horses. For example she will refer to a clydesdale that she sometimes rides as 'my own/my gorgeous clydey' when infact she doesn't own the horse. She likes to portray to others that she's an experienced and confident rider. If you ask her a horse related question she'll go off on a tangent sort of making up stuff as she goes along. (this may sound very harsh of me but its not my intention)

I'm just asking because I don't know alot about horses (and will be the first to admit it) and I'm not sure whether my doubts are true or she'll be fine.

I totally understand. Some people are like that. It's not a bad thing, it's just that they're very confident in what they do, and if they don't know the answer to something, they have confidence that they can figure it out. Sometimes they can get a little (or alot) arrogant, or at least sound that way unintentionally. Sometimes I can be that way, though I'll be the first to admit that there is a butt-load of things that I still have to learn about horses, and that I am often wrong (thus still learning). I think that she'll be fine so long as she stays open-minded and keeps learning things from every point of view. As far as safety goes... Tell her to keep her helmet on and hold on for the ride. If the horse is green I would be more concerned, but if the horse has done well for her in the past... well, every horse is different. And the more times she picks herself up out of the dirt, the quicker she'll learn. I've learned alot that way. Dirt doesn't taste all that great and it can be a great opportunity for a reality check! ^^

I say for you you might want to just stand back from that situation. Now I know there are alot of people out there that do thinks that some people think are dangerous but they have never had a problem. I think God watches out for those people. If it looks dangerous to you don't do it. Keep learning and growing in your abilities.

As to the title of your post, yes it is VERY possible to teach an old horse natural horsemanship (since natural horsemanship works off of the horse's natural instict and language, which ALL horses know). I started my Arabian mare in NH at 17 and she picked it up like a pro. We go bareback all the time in a halter or just with a rope if we are in the arena or field.

As for your actual post about your friend, I would personally suggest her getting the basics down first before trying NH. NH involves alot of instinct and imagination, by which you have to be able to understand the horse, how, why and when it responds to certain stimuli, and above all how to know when to apply and release pressure.
If she doesn't know this (and novices typically wont) she could end up doing more damage than good and just confuse the horse.

Thanks for your replys. I think I'm just going to keep out of it and let her do as she thinks. I don't think she'd put herself in any too grave danger anyway.
Thanks :)