Actually, by pre-screened I think they mean they go through a screening process after they "surprise factor".
Meaning they hail the cab, they get in, they find out it's the cash cab. The tape stops rolling, the producers talk to them and if they agree to continue well, then they do.
And Raspberry, not all cab drivers do that.... Not for nothing, I think I actually see more regular drivers do that, than I do cab drivers. Then again, it's been years since I've taken a cab. If Im not in my own car or on the subway, I walk. ESPECIALLY with the fare hike.
"You're every gay man's wet dream!" ~ MA
If in Heaven you don't excel, you can always party down in hell...