Not only does it reduce the revenue from the discount applied but additionally with the labor and material of your logo, whether it be printed or vinyl. Will the gas station give you a discount on gas if you put their logo on your car window? You have to remember a rec league or school sport season isn't very long so that advertising you do on the shirts is not going to be out there long time. To be honest I think only those of us in this business pay attention to what is on a shirt. Anyone else is too focused on the kids. My opinion.