The reality is, you get so little time to really judge a boxes appearance, it walks by you, and sometimes rather quickly, maybe a few seconds to see the entire thing. If the meat really rocks, it hardly matters what the greenery looks like, as the judges (all meat eaters) will be looking at the meat. If the meat is blah, then their eyes will wander. But, sometimes, despite your best efforts, the meat does not really rock, that is when a few points, or fractions thereof, just might lift you up a spot or two.
And you can control garnish absolutely with some preparation. There is rarely a reason for a bad garnish. Meat appearance is much tougher. Since the rules allow garnish, and really, you pretty much have to do it, why not work at getting the easiest thing to control right. I happen to think it looks nice to have it in there. Although, show me a box filled with really nice ribs or great chicken, I won't see the greenery at all.
I'm feeling bearish, and I'm packing a Wusthof Grand Brisket slicer from MABA
"perhaps...but then again...maybe not..."