This at first seems frivolous but after considering it I have to side with In-N-Out. Consumers may think this company is an authorized/official delivery service

This at first seems frivolous but after considering it I have to side with In-N-Out. Consumers may think this company is an authorized/official delivery service for In-N-Out, and if In-N-Out can't be certain of the quality of the service that's going to possibly reflect badly on them.