Horse Training

Just wondering, what if one or more people tried using this to make money, be it emeralds, EB, or even LE?
Anyway, it would basically be like this:
Two people talk about this with each other, and make an arrangement.
Some Stuff happens XD And then they meet again (unless they are already prepared for the following transaction, the main part of my idea)
**********
A trade occurs. One person offers a fully trained (or close to this, depending on trader preference) horse
The other person offers a lowly trained or untrained horse of the same tier, as well as a sum of money.
**********
So what do you guys think? Is this a good idea? And what do you think the "training fee" for different horse tiers should be?

 

People already do this
Occasionally
Usually it doesn't happen

 

True, although you don't, or at least I don't, really see advertisements looking to train a horse or offer a trained horse for an untrained one in exchange

 

Because no one wants it
I know @GlitchedSlayer tried it sometime ago, and there's been like one buying thread on it

 

Thing is, no one will pay to have their horse 'trained' and it spends hours to do so anyways

 

Yeah especially with the whites