I do script my presentations. Over time, what I've scripted has become more detailed - it used to be concepts and certain lines or jokes, but now I script everything. The words, the expressions and what the audience sees happening in the effect.
Scripting is the best cure for "say-do-see" patter and for bad story patter. Seeing what you are going to say in writing tends to keep you from saying what you are doing or talking about things that only are interesting to you.
It also provides you with an opportunity to EDIT your patter so that it only contains what is necessary for presenting the effect. What I mean is that:
"One day last week I went out with this girl who was a friend to Burger King and after we ordered our food we sat at a table and she told me about her grandmother who used to read tea leaves and predict people's futures."
Becomes this:
"One of my best friend's grandmother used to read tea leaves."
That is, you need to take out everything that isn't essential. That leads to clarity in the audience's mind.
One of the other considerations in scripting is providing the necessary motivation, misdirection and implanted memories in your audience. The motivation is the justification for doing something that might otherwise look out of place like showing the cards as being shuffled while you cut a certain card to the bottom of the deck. Misdirection or more aptly re-direction is focusing your audience's attention where you want it. The patter itself provides misdirection in that it gives the audience something else to focus on, but through scripting you can build in further misdirection by writing patter that actively directs their attention to something else. Finally, implanted memories are devices you use to have the spectator remember something different than what actually happened. Here, subtlety matters. You have to build in suggestions and provide time misdirection. It isn't something that you can do without thinking about it in advance.
Scripting isn't easy but it is with it.
I'm not sure why you're saying this. I said nothing regarding Penn & Teller. I was talking strictly about Teller, not his work with Penn. My point was not about the scriptedness of their show, it was about Teller as a performer.
Every action and expression that Teller makes is scripted. Scripting isn't just words, but actions and expressions and EMOTIONS. By emotions I mean what you convey to your audience - wonder, excitement, sarcasm, humor, etc. Teller doesn't talk but he does communicate more without talking than most performers do with talking.
