A presiding judge (presiding over the case) has a duty to control his/her courtroom. There can clearly be pre-trial restrains on the conduct of attorneys and their staff (because the staff is under the control of the attorney who is an officer of the court), court staff, named parties to the action or proceeding and sometimes witnesses. Being on a witness list may not be enough. Being under subpoena as a witness for trial in this matter may be enough. It is a matter of criminal procedure and that would be a matter of state law. So, you would have to look to Florida laws on criminal procedure and Florida case law for this guidance. Just having an attorney put a name on a witness list may not be enough because the attorney can put anybody on that list; including their disliked in-laws or next-door neighbors. A witness list is just discovery information; not nexus for in personam jurisdiction. So, there has to be some nexus to the case and some point where for the purpose of controlling the procedure of a trial, the presiding trial judge gets in personam jurisdiction over the witness.
Sorry for the long answer to a short question.
