Customers.....would be correct terminology for someone paying for a service I think.
The guys and girl at Maroochy are always very helpful and polite. I do recall the lady ATC there during her first few months get a bit tongue tied and so on, clearances took a little longer etc, and now she is up to speed and a delight on the radio.
We all need remember what it was like to be the student at the bottom of the food chain once in a while!
Some folk definately should learn fluent english first though!
J