Now room for "honest mistakes"

USA Women's Soccer goalie Hope Solo tested positive for a banned substance and received only a warning from the US Anti-Doping Agency.  I understand that WADA tweaked the rules a little bit in 2009 to allow for "honest mistakes," or those cases where athletes take some sort of medication for a legitimate, non-performance-enhancing purpose and the medication contains a banned substance.  Considering suspension too harsh for these "honest mistakes," the USADA can now give warnings.  But I just wonder what kind of slippery slope that will create for honest mistake doping??  We'll see!