What reasons does Atticus give for the children not to play the Boo Radly game? Do you think he is right ? Why?

One day Atticus catches them playing the game and asks them if it has anything to do with the Radley family. They deny it, and Atticus replies, "I hope it doesn't."

“Give me those scissors,” Atticus said. “They’re no things to play with. Does this by any chance have anything to do with the Radleys?”
“No sir,” said Jem, reddening.
“I hope it doesn’t,” he said shortly, and went inside the house.