No matter what the rules say.. it's part of the game.
Top notch garnish arrangement will make the meat standout.. Attention to detail w/garnish can also positively affect the taste score before it is even sampled (as wrong as that may be). A judge may be more apt to have pre-conceived idea that it will taste good and will have a harder time scoring it down if it looks like it should taste good.
As much as most might say they don't judge the garnish, it has to have some subliminal effect for some judges.. and that's all that might be needed to get a better score/placing.
Also remember - not every contest has 100% CBJ's..
Lonestar 24" Vertical offset w/ Insulated Firebox & Performer Platinum
Former owner: Jambo Backyard, Klose BYC, Med. Spicewine, Pitts & Spitts, XL & (2) Med. BGE's, 22" WSM & (2) 18" WSM's, 18" & 22" Weber Kettles