Jon decided to make it so everyone that makes a wish with a wishbone would have their wish granted. He thought that not too many people would be wishing that way, so the number of people would be limited. He didn't want it to get out of control.
He wished it and the stone flashed.
Feeling better about the charitable thing that he had just done, Jon continued to walk home.
But, even a small amount of people wishing could get out of control, as Jon will soon find out.