From the summer '05 Buckeye Newletter there's an interesting comment on DQ's based on Stem on Stem in Dr. Jim Hering's column.
Here is a link that might be useful: Buckeye newsletter
D/Qing for stem-on-stem has always been a rule that I have never quite understood -- maybe we have some finer minds than mine that can answer this.
My feeling is the we judge from the top of the vase up. Who cares if there is a dogleg -- way down below.
Because we allow wedging and don't allow stem-on-stems, many times a rose with a short stem is wedged at the very top of the vase with very little stem underwater. And what happens -- after a few hours (sometimes before the queen is judged) the rose wilts.
Also - some shows have milk-glass vases or even amber beer bottles.
Seems like negative judgeing to me.