One evening, they decided to visit a local bar.
“Be careful of scammers,” warned their tour guide. “There’s a lot of dishonest people in this neighborhood.”

Dave shrugged and laughed. “Don’t worry mate, I can always spot a liar.”

They went to the bar. At the door, the bouncer stood with his arms folded. “I’m going to have to see some id, gentlemen.”

Johnny was furious, and started protesting. “Of course we don’t have id! I’m 46!”

Dave pulled Johnny to the side, and whispered “Shut up and let me handle this! He’s no doubt used to dishonest people.”

Dave approached the bouncer, winked and pulled out 20 dollars (or whatever the local currency was). “Here’s my id, sir.”

The bouncer stared, and said “Sorry, I can’t take a bribe.”

Dave pulled out $50. “How about now?”

“Sorry, it’s against the law.”

Dave pulled out $100. The bouncer stared longingly at the money, but still refused.

Dave pulled out $200. The bouncer frowned. “All right then. Much as I hate breaking the law, this is more money than I’d earn in a week. You can enter.”

Dave and Johnny entered triumphant.
After a few pints, Dave got chatting with the bartender.
“You should know, your bouncer is surprisingly honest. I didn’t expect in a neighborhood like this to find a bouncer so hard to bribe!”

The bartender laughed.
“We don’t have a bouncer.”