::You don't see how silly it is to use tickling as torture? Some significant percentage of the population simply is not ticklish. Even those that are don't care that much and will get bored of it in time. 
 I disagree - for those who are ticklish it really is sheer torture! Personally, I have been tickled (in the sides) to the point of hyperventilation and find it incredibly unpleasant. I can quite easily see how effective it would be as a form of torture. Actually, intense tickling tends to bring about fight or flight and I've seen quite a few of my friends get violent when trying to extricate themselves.