This, this is exactly what happened in every session of Mask we've run so far, and it's been beautiful, just beautiful, to observe:
"One interesting observation is that when you flat out tell the players that there isn't really anything prepared and that you're basically winging it, then player paranoia goes WAY down and they become a lot more proactive. They stop asking a lot of repeative questions of NPCs and stop trying to turn over every minute rock and scavage for every detail known to man before deciding to take action. Basically, they stop trying to second guess the GM when they know there isn't anything to second guess." - from an Actual Play report involving Werewolf: the Apocalypse, by Jesse, aka jburneko, at the Forge.
People are basically considerate and thoughtful creatures, once their basic physical needs are met. Players never, ever want to risk "ruining" your carefully planned adventure, provided they think or know you've planned something. The exception is, of course, if they aren't enjoying what you've put together, but even then, I bet I could go back and interview old players and find out that those who didn't like what I was doingjust didn't want to say anything.
That's okay with me; I kind of freak out when people make their displeasure too plain (see: my Changeling posts on my Livejournal account). Finding a technique that puts the plans of the entire group the table is much more exciting! Huzzah.
Here's hoping we play on Saturday, as planned. I'm seeing Watchmen with friends on Friday night, and it had better not suck.