Common sense tells us that you should watch for indications that your client (or the other lawyer’s client, if you have met him or her) may have some tendency to violent behavior. Uncontrolled outbursts or profane language in a nasty tone of voice would be obvious signs. Threats, of course, should be taken seriously and reported to law enforcement when appropriate. Yes, there are limits to what you can do. But do what you can!
Little did I know when I wrote this how timely it would be. If only, if only more people followed this simple advice.