Was the experiment conducted in a vacuum? It would seem to me that in order for this experiment to be conclusive it would require that ALL possibility of outside variables be eliminated. Since atmosphere would interact with any particles in motion, it would inevitably taint the results. I also suspect that the nature of atomic structure would introduce interference related to the positive and negative charges individual atoms possess. In addition, I believe that gravity could also create variables that are detrimental to the conclusions drawn from the experiment. I'm not sure, given the current state of technology, that the double slit experiment was able to sufficiently eliminate outside interference.
It is an interesting experiment. However, I'm not convinced that sufficient efforts were made or could even be made to produce conclusive results. That is precisely why what we believe to be scientific fact is always changing. As we gain understanding we inevitably find ourselves rewriting what was previously thought to be infallible. It is also why our imaginations constantly ponder the "what if" that has created so many science fiction authors.