A Scotsman is sitting in a bar in Cuba and is minding his business when a man with a large black beard walks in.

The man goes to the bar and orders a shot of whiskey.
The bartender serves him, the man drinks the whiskey then starts walking out the door.
The bartender says, "Hey aren't you going to pay for that?"
The man says, "Excuse me, Fidel Castro's Army."
The bartender says, "Alright then" and the man leaves.

A few minutes later another man with a large black beard walks in.

The man goes to the bar and orders a shot of whiskey.
The bartender serves him, the man drinks the whiskey then starts walking out the door.
The bartender says, "Hey aren't you going to pay for that?"
The man says, "Excuse me, Castro's Army."
The bartender says "Alright then" and the man leaves.
The Scotsman gets an idea and walks up to the bar and orders a shot of whiskey.

He drinks the whiskey then starts walking out the door.

The bartender says, "Hey aren't you going to pay for that?"
The Scotsman says, "Excuse me, Castro's Army."
The bartender says, "Hey where is your big black beard?"
The Scotsman thinks quickly. He lifts his Kilt and says, "Secret Service!"