Our company does a lot of marketing and sponsored events. You have marketing events and sponsor other events for marketing purposes which is exactly what they did here. They donated gifts to the event in return getting advertisement to xyz people and increasing sales/traffic to there door. At some poi t that $50 is coming off there bottom line so why piss off a customer in the process. Look at the big picture....take the card and its done and off the streets so the customer leaves happy and will likely return for more parts or service. Worst case he never returns but maybe he sends someone your way but this negative thread wouldnt exist.
Narrow minded business puts many companies out of business. If he donated too much money for the possible return of business from the event thats something they should adjust next year.