A mail order business, operating out of a PO Box located in a popular shopping mall, was using the same exact trade name used by an insurance company for senior care coverage. Their law firm, said they needed to identify and locate the business' principals so that a "Cease and Desist" letter could be served on them to have them refrain from using the trademarked name.
A unique package was sent to the known PO Box from the same town to increase the chance of delivery by the next day. The following day, the package was seen being unloaded by the US Postal Service deliveryman. The entrance to the business center was watched and a colleague was ready to roll in the parking lot. Two young men were observed retrieving the PO Box' mail, they were tailed to a residence approximately 4 miles away.
The "Cease and Desist" was served later that day.