Ah, that makes sense. :) -lightbulb goes on-
I ride dressage and I've always been told that the right is the proper side for the mane.
My mare's mane falls to the left so I just leave it that way. -shrug- For one show I braided it on the right side and for the other show I braided it on the left. I think as long as the mane looks tidy, it shouldn't matter (in shows). Afterall, the judge isn't going to be judging your grooming skills when you're doing a dressage test. :P
maybe not while you are doing the test but presentation is included in your marks. Some judges are super over the top about tradition etc when it comes to grooming (and many other things)