I'm not sure about it being 'cheating' or 'shameful'...but it would certainly be something the tennis authorities should find a little disturbing.
I find it concerning that players these days can pretty much walk out on court in whatever colour and style of clothing they desire.
It's all about corporate dollars, clothing sponsorships and fashion statements.... and so in a lot of ways tennis is just following along with the rest of the world.
It appears that to be a purist in this modern sporting world is in itself 'unfashionable'. Ahhhh...the irony