I may be mistaken but a clean ditch doesn't count as a death in AH. The D in K/D is DEATHS.
I think they count your deaths, bails, and captures, unless my cursory ratio estimates were wildly wrong. I support this rationale in my mind as "reciprocal and sensible" because, after all, you are awarded a kill even if your opponent merely bails and is not splattered, popcorn-ceiling style, all over the MA (which I 'd like to see made persistent so that his bits of brain and blood would remain as a subtle form of trophy).
But there I go, raising the subject of nutraceuticals again...