Affiliated I think you'll find you can't have coloured piping or embroidery (other than a sponsers logo i blieve?) But anyone feel free to correct me if i'm wrong
Nope, in affliliated you cant have piping or embroidery, only a sponsers logo (My trainer has always taught me this is a sign of good manners on your part). Unaff I dont really think it should matter too much!
Personally I think it looks much smarter to have just a plain white one anyway. I'd hate to put a white saddle cloth with pink piping on my horse and take him into the dressage arena. He'd think he looked a right twit I should think!!