i dont see this as a problem for the AFL/ASADA. it's a problem for the players and the people that lied to them. But for the AFL/ASADA it has to be clear cut. you took the substance, you get banned. That ban would be reduced if they openly admit to what happened and assist with the investigation.
it's tough, but it's the only way unfortunately.
Not sure if this is the most up to date AFL Anti-Doping Code, but it does provide for penalties being reduced or eliminated entirely in certain circumstances.
http://www.aflcommunityclub.com.au/fileadmin/user_upload/Play_AFL/AFLAnti-DopingCode2010ASADA.pdf
AFL Anti-Doping Code said:14.4 Elimination or Reduction of Period of Ineligibility Based on Exceptional
Circumstances
a) No Fault Negligence
If the Player establishes in an individual case that he bears No Fault or
Negligence for the violation, the otherwise period of Ineligibility shall be
eliminated. When a Prohibited Substance or its Markers or Metabolites is
detected in a Player's Sample in violation of Clause 11.1 (Presence of
Prohibited Substance), the Player must also establish how the Prohibited
Substance entered his system in order to have the period of Ineligibility
eliminated. In the event this Clause is applied and the period of Ineligibility
otherwise applicable is eliminated, the Anti Doping Rule Violation shall not be
considered a violation for the limited purpose of determining the period of
Ineligibility for multiple violations under Clause 14.6.
(b) No Significant Fault or Negligence
If a Player or other Person establishes in an individual case that he or she
bears No Significant Fault or Negligence, then the otherwise applicable period
of Ineligibility may be reduced, but the reduced period of Ineligibility may not be
less than one-half of the minimum period of Ineligibility otherwise applicable. If
the otherwise applicable period of Ineligibility is a lifetime, the reduced period
under this section may be no less than eight (8) years. When a Prohibited
Substance or its Markers or Metabolites is detected in a Player's Sample in
violation of Clause 11.1 (Presence of Prohibited Substance), the Player must
also establish how the Prohibited Substance
entered his system in order to
have the period of Ineligibility reduced.