I wasn't thinking as far as you did. I thought if it is a case that this judge cannot be objective because she has been judge so many cases that involved MJ?
I found this:
So they’ll step aside in several instances. If the judge:
Is related to a party, attorney, or spouse of a party in the lawsuit
Is a party to the lawsuit
Is a material witness in the lawsuit
Was previously involved in the case (for example, he was a party's lawyer)
Prepared the contract, lease or will involved in the case
Is an appeals court judge and was the trial judge in the same case
Has a personal or financial interest in the outcome
Believes, for whatever reason, that he or she cannot be impartial
These factors are similar because they are specific and involve a direct connection between the judge and the case.
http://research.lawyers.com/Well-Recuse-Me-When-a-Judge-Shouldnt-Try-a-Case.html
It says previously involved the case, so I loosely translate it that involved any case relating to MJ
