The Grinch

*<- May or may not have bought 1 kg of Mars/Snickers/Dumle to give out tomorrow*

I'd say that this would be hilarious, were it not for the fact that you would probably feel really sick around the time the 10th pair of children arrive. 

@Tartar I'd go through with it despite feeling sick, I think you underestimate how much I'd love to see the dissapointment in those little faces every single time

You would pretty quickly get a reputation as the grumpy  old man of your town, and kids would start avoiding you. I think it'd be more fun to run it as a long con, every 10th group orso you pull this, while treating  every single other group very generously. You have some kids bragging about how much candy they got from you, while other groups get crushed by utter appointment. 

You get the pleasure of building up expectations, then crushing them while at the same time not feeling super sick. I'd say it's a win-win.