The Leaky Cauldron.
An Egyptian wizard wrapped in black robes was questioning the proprietor, Tom, in halting English. "So, this place can't be seen by Muggles?"
"No. I refresh the Muggle-Repelling Charm every day," Tom said.
"What sort of wizards come here?" the other man asked.
"What do you mean? Lots of people come here because some young wizards need to enter Diagon Alley through this place," Tom said.
"Have you verified their identities?"
"What?" Tom froze. "Verify whose identities? The people entering the pub? How could that be possible?"
"Then how can you be sure they're all wizards?"
"Muggles come here too. Muggles also need to pass through here to enter Diagon Alley," Tom tried to explain.
"So Muggles can know about this place?"
"Yes, but that doesn't affect—"
"As the gateway to the wizarding world, have you never considered the risk of exposing the existence of the wizarding world?"
"No, I mean, those Muggles are usually taking young wizards to Diagon Alley to buy things. They need to exchange money... and young wizards need to be accompanied by their parents..."
"You haven't verified their identities. How can you be sure they're the parents of young wizards rather than ill-intentioned Muggle conspirators, anti-wizard extremists like Second Salem?"
"I, I..."
"Oh! Merlin's boils! Enough!" A wizard who had been drinking slammed his glass onto the table. "Leave the poor man alone. He's just an innkeeper. He doesn't need to bear the responsibility of protecting the wizarding world!"
"And you are?" the Egyptian wizard asked.
"What, are you going to write down my name?" The man glared at him viciously. "Do you investigators have nothing better to do? All you do is harass people all day!"
"I must correct you. Complying with the International Statute of Wizarding Secrecy is every wizard's