When someone approaches you while you’re on duty and extends their hand for a shake, do you reflexively oblige, even if it’s someone you know isn’t really interested in sharing goodwill, like a known gang member or a crime suspect? If so, it’s worth the effort to de-condition yourself from doing that. In essence, what you’re doing with that hand shake is allowing that person to “grab” you and to control your right hand, which for many is the strong hand. With that, you can be pulled off balance, yanked inward toward the suspect, prevented from drawing your firearm if you’re right handed, and prevented from quickly pulling away and creating distance. It also puts someone who’s intent on disabling you in a position to easily slash your forearm.
It’s understandable to be thinking that a handshake might help you keep the peace, develop rapport and prevent a negative public relations image, but from a tactical standpoint, refusing a handshake and quickly offering the comment, “I don’t shake hands on duty. You understand.” is a lot safer for you.