Light $\stop\to\wino b$ models are not ruled out by the Tevatron top   experiments
  SUSY events in which a light stop decays to a chargino may manage to pass the cuts designed for top counting experiments at the Tevatron with no significant diminution of signal. Events in which a top decays via stop are detected with fair efficiency compared to SM top events when $\stop\into b\wino$. More importantly, direct pair production of light stops contributes significantly to the cut samples. Many SUSY models with stops lighter than 100 GeV are viable even for $\Gamma(t\into\stop) \approx \Gamma(t\into bW)$. 
John Sender (University of Hawaii)