From joystiq.com:

During the Xbox Live Enforcement panel at PAX this past weekend, director of policy and enforcement on Xbox Live, Stephen Toulouse (a.k.a. Stepto), recited "Stepto's Law" for the audience. The complex formula is used to determine the validity of a complaint issued by a banned Xbox Live user. The law goes like this:

"The more convoluted, overwrought and lengthy the protest of innocence, the probability of it being bullshit approaches one."
Full Story: joystiq.com