Bing I don't know how far back you've gone in this forum, but Kniferights.org already had a semi-successfull outcome with one of the knife arrests.

http://forums.equipped.org/ubbthreads.php?ubb=showflat&Number=212060&page=1

I'm not entirely sure why the DA backed down. If I were in his shoes I would wait till I had a career criminal instead of a first time offender with a legitimate reason to go after. It would be risky setting a precedent with a "good guy" defendent.
_________________________
Hope for the best and prepare for the worst.

The object in life is not to be on the side of the majority, but to escape finding oneself in the ranks of the insane