Delivery notes are there to help takeaway drivers get to their destination. Usually, you'll see information about door codes, where to park, or how to contact the customer. This warning is a lot more specific, and a lot scarier, too!
Why there are ninjas in someone's parking lot is anybody's guess, but at least the delivery driver has been warned to keep an eye out for them. We still think it's probably a matter for the police, though.