I always skip those stations too, unless I have no choice, but for Costco I don't care. Only because I know they have their sh*t together. Or at least mine did.
The thing is additizing the whole time the trucks are unloading and it's designed to maintain consistent additive levels in the fuel it's dispensing while the trucks are unloading. That's a selling point of the system they use. And they're getting several deliveries a day, so you gotta figure there's probably 100 cars a day, everyday, pumping gas while the truck is unloading so if something was really wrong with it I figure people would complain.
Everywhere else though ya I just drive to the next station