I don't really get this from an operational standpoint. Surely it takes about 5 minutes tops to go into a staff room and change a shirt. Or wear an MRT polo over the top of the existing shirt.
What makes this more bizarre is that it's not even specific for each park. Surely it's not that hard and not that more expensive to make a MW/SW/WNW specific polo with the park logo instead of a generic Village one. Some rides are affected by this worse than others. Superman and Scooby are the big ones pointed out previously but Justice League, Storm & WWF can be added to the list. You can probably get away with it on Lantern, Rivals, JDS and most of the shows.
LPS have specific operator shirts just for Big Dipper, I would like to imagine Village Roadshow who charge a triple digit sum for a day ticket would be of a similar standard.