I would NEVER judge down for a bit of parsley (or more than a bit even) It is the meat we're judging, not the garnish.
I do sometimes leave a little parsley on my judge plate though, in case a particularly strong tasting entry numbs my tastebuds, a bit of parsley, followed by a saltine and a swig or two of water makes for a good palate cleanser
The one thing I was surprized by as a judge were the number of REALLY hot (spicy hot, not heat hot) entries that are sometimes turned in, particularly in chicken and ribs categories.
While I really like spicy food, some of these have been so peppered that my taste buds go pretty much numb, meaning I have to let them recover before I can taste the next sample objectively. I would definitely advise folks to save the 3-alarm spice level for home and freinds, and not let it loose at contests. Again, it really should be about the meat, not the sauce or rub.
Sorry, didn't mean to hijack this, I'll get down off my soap box now!