How Tristan Survived King and His Knight's Fate

[Edgardo]

Once upon a time, there was a king, who found out that his wife, the queen, had an affair with Tristan, one of his knights. He gets mad and calls all his knights and Tristan:
"I found out that you have a relationship with the queen, Tristan. Tomorrow morning, I will give you a bag with 3 white stones and 1 red stone. If you pick out the red stone, you are a free man. But if you pick out a white stone, you will be executed."
In the evening, the king prepares the bag with the stones. But he wants to get sure that Tristan picks out a white stone, so he puts in 4 white stones and 1 red stone to increase the probability of picking out a white stone.
The queen notices that and during the night she tells Tristan what she saw.

The next morning, Tristan is called to come to the king and his knights. The king gives him the bag.

How does Tristan survive?

 

[BicycleTree]

He covertly pours red paint into the bag just before reaching in? He tells the queen to switch around the stones? He asks her to find out if the red stone has a noticeable shape? He looks inside the bag? He uses some sleight-of-hand with another red stone? He uses a magnet (assuming the red is iron)?

 

[DaveC426913]

As with the riddle of the daughter and the black and white pebble:

The Knight dumps the contents of the bag on the table for all to see, and let's the rest of the Knights deal with a cheating King.

(Not really the answer, but I've never understood why anyone who is forced to play a game concedes to playing by the rules.)

 

[Edgardo]

LoL, Dave got it. But please put the letters in white so others can't see the solution.

 

[T@P]

what about going up to the bag, making a scene, cutting his hand (now over the bag), let the blood drip into the bag and then picking out a stone?

 

[Edgardo]

LoL

 

[DaveC426913]

LoL, Dave got it. But please put the letters in white so others can't see the solution.

I did? I didn't mean to! Surely that's not the answer!

I assumed it was a variation on this teaser!

 

[DaveC426913]

what about going up to the bag, making a scene, cutting his hand (now over the bag), let the blood drip into the bag and then picking out a stone?

Ooh. That's a good one.