They have done it for years off and on. Farm or Stable colors, Hanover, John Simpson Sr. originally Maroon and white. Arden Homestead, Lady J, Goldfish, she is now wearing her own Green red and white/ Clearview Farms (Norman Woolworth)Duenna, Stanley Dancer, Hambletonian. Lindy Farms etc. It's not up to the trainer, it's up to the owner. You want to drive do what the ask.It's also easier for the owners to see their horses. This is how the T-breds have always done it.