Interesting comment from here about how McCain's campaign placed teleprompters so he would look more natural giving a speech:

I wish that once, just once, the cameras would show us what is really going on in these rooms. It would both legitimate and honest to show the candidate making a speech AND the teleprompters AND the cue cards/big screen TVs etc. Why does the media allow politicians to get away this fiction that they have memorized their speeches and are delivering them extemporaneously?

I'm all for breaking down the fourth wall, but does anyone actually believe this fiction anymore? And if they don't, when did they stop? "They" being American audiences, consumers of political theater? If a scholar of political communication were to take this on as a topic, I would bet they'd look at the construction of extemporaneity as a rhetorical choice -- but not at how people perceived said construction/fiction. Perhaps the fiction is not so much rhetorical as it is ritualistic: a summoning of the order of the universe through the repetition of what has been and what will always be. Which is why it would look strange if the fourth wall were broken, not because the interaction would be less persuasive but because it's a threatening departure.