I guess I'm the odd one out...I had no clue what most of you were talking about for a few posts. (Yes, I'm usually slow on the uptake.

)
We started hiding a pickle ornament when DD was about 5 - because it took my that long to find one I liked. I wanted something small that was hard to find. (Yes, I'm mean, too.) Mine is tiny like a gherkin and is about the size of the last 2 knuckles on my pinky. I just don't get the purpose of "hiding" something the size of a Kosher Dill.
I usually have an ornament for the person who finds the pickle on the tree. I just wrap in Christmas paper...I much prefer the plain, brown wrapper with pickles stamped on it though!