In addition to lacking subpoena power and legal standards, the presence or absence of aggravating and mitigating circumstances affects the penalties levied in NCAA infractions cases.
Aggravating circumstances warrant the imposition of more severe penalties in an infractions case. Mitigating circumstances warrant the imposition of less severe penalties in a case. Aggravating circumstances include but are not limited to an institution's history, and the school's cooperation with the NCAA during an investigation. If you fail to cooperate or try to conceal violations, you are subject to more severe penalties. Conversely, if you exhibit exemplary cooperation or have little to history of rules violations, you may be given less severe penalties.
It may seem axiomatic that cooperation mitigates potential penalties in an infractions case, but without subpoena power the NCAA must put a premium on openness. Otherwise, it would be extremely difficult for the NCAA to discover relevant information in a given case, because there would no incentive for schools to do so.