I've just had another thought on that; school-age kids (excluding those old enough to have part-time jobs) have no idea about customer service, and they came to the door (door-to-door selling wasn't prohibited in NZ, although I have not seen it over here) and very unenthusiastically said "wanna buy some lollies?", while standing there with a box with a range of different types, acting as though you know what's in there.
In High School though, it's a lot different, because only those participating in the event or trip the money is being raised for, have to do it. It's also a lot easier in high school (from watching others doing it) because door-to-door selling isn't required - all you have to do is have your box with you and people will see you and go and buy one.