Well, think about it. Contacting every good divorce lawyer in town in attempt to conflict them out so that your spouse cannot hire them is nothing more than manipulation of professional conduct rules to obtain an advantage in litigation.
Judges are people and they're typically (though not always) fairly smart people. And they take rules and fairness seriously. They know when someone is trying to play the system.
Certainly a person is entitled to do some market research and interview a few lawyers before selecting one. But a systematic effort to create conflicts of interest is something that could be easily brought to light in a deposition.