Salesman from competing company following delivery trucks to steal customers

Location: Florida

So this is story I've been told. One of the delivery drivers mentioned to the boss that there's a car that follows him while he delivers. Its been going on for a few days. The following car never makes contact with the delivery driver, just tails him everywhere he goes. Boss decides to follow his own delivery driver one day until this car shows up. Like clock work the car appears. Boss confronts driver and asks him why is he following his driver. Guy says hes a salesman and confesses he's following to see which customers we deliver to so he can go in and offer them a lower price. Boss tells him the following stops today. If he sees him following his drivers again he'll call the police.

My question, is there any legal standing to stop this salesman from following the delivery trucks since he never makes contact with the drivers?