I'm a little disappointed to hear people defending discourteous behaviour from flying schools on the justification that courtesy is to be granted on the basis of potential profit. If they’re not actually giving us money then we can’t afford a smile, least of all a cup of coffee.
Like the people that don't think to hold a door open for you, and don't say thank you or even smile when you hold a door open for them, presumably as you’re not paying them.
Of course there may be a limit to how much time a business can give to someone that isn’t a customer and isn’t likely to become one. But a lot of courtesy really does cost very little. It makes both the giver and the receiver feel better.
Courtesy isn't a business decision; it’s the mark of a civilised society.