Well, we could employ something along the lines of the following logic to vet out the candidates. Couldn't be any worse than what we have today and would certainly be more entertaining...
How to Tell a Witch...
Villager: We have found a witch, may we burn her?
Crowd: BURN!! BUUUURN HER!
Bedevere: But how do you *know* she is a witch?
Villager: She looks like one!
Other Villagers: Yeah! She looks like one!!!
Bedevere: Bring her forward.
(a young woman is pushed through the crowd of villagers to the platform. She is dressed all in black, has a carrot tied around her face on top of her nose, and a black paper hat on her head. She talks funny because her nose is closed by the carrot.)
Witch: I'm not a witch, I'm not a witch!
Bedevere: Er,...but you are dressed as one.
Witch: THEY dressed me up like this.
Villagers: No! nooo! We didn't! We didn't!
Witch: And this isn't my nose, it's a false one!
(Bedevere lifts up the carrot to reveal the woman's real nose, which is in fact rather small.)
One Villager: Well, we did do the nose.
Bedevere: The nose?
Villager: And the Hat. But she's a witch!
Villagers: Yeah! Burn her! Burn! Burn her!
B: Did you dress her up like this?
Villagers: NO! No, no, no, no, no, no...
One Villager: yes.
Villagers: yes. yes. yes. A bit. yes. a bit. a bit.
Another Villager: (hopefully) She has got a wart...
B: What makes you think she is a witch?
Villager: Well, She turned me into a newt!!
Bedevere: a newt?
Villager: I got better...
Villagers: BURN HER anyway! BURN! BURN! BURN HER!
B: Quiet, quiet, quiet, QUIET! There are ways of *telling* whether she is a witch!
Villagers: Are there? What? Tell us, then! Tell us!
B: Tell me. What do you do with witches?
V: BUUUURN!!!!! BUUUUUURRRRNN!!!!! You BURN them!!!! BURN!!
B: And what do you burn apart from witches?
Villager: More Witches!
Other Villager: Wood.
B: So. Why do witches burn?
(shuffling of feet by the villagers)
Villager: (tentatively) Because they're made of.....wood?
Other Villagers: oh yeah... oh....
B: So. How do we tell whether she is made of wood?
One Villager: Build a bridge out of 'er!
B: Aah. But can you not also make bridges out of stone?
Villagers: oh yeah. oh. umm...
B: Does wood sink in water?
One Villager: No! No, no, it floats!
Other Villager: Throw her into the pond!
(when order is restored)
B: What also floats in water?
Another Villager: Apples!
Another Villager: Uh...very small rocks!
Another Villager: Cider!
Another Villager: Uh...great gravy!
Another Villager: Cherries!
Another Villager: Mud!
Another Villager: Churches! Churches!
Another Villager: Lead! Lead!
King Arthur: A Duck!
Villagers: (in amazement) ooooooh!
B: (to a villager) So, *logically*...
Villager: (very slowly, with pauses between each word) If...she...weighs the same as a duck......she's made of wood.
B: and therefore...
Villager: A Witch!
All Villagers: A WITCH!
(they do consequently weigh her across from a duck on Bedevere's largest scale, and she does indeed weigh the same as the duck.)
Witch: It's a fair cop.
Copyright Monty Python , from Monty Python's The Holy Grail.