No. I think it's because you're trying to draw the eyes of the defense into the interior of the line on your base running plays. If you're "trick play" also moves into the middle of the defense, then you're playing right into where you want your opponent to be.
Chris Brown talks about designing and offense in his book Smart Football as essentially two sets of plays--your base offense (i.e., the stuff you do well) and "tendency busters", those plays that you turn to when opponents start making predictable adjustments to what you do well.
I think that the design of our offense is to draw opponents into the area of the field outside the hashmarks between the line of scrimmage and 10 yards downfield. Our "tendency busters" are therefore runs into the area between the guards and deep passes to the corners or down the seams.
That's why we keep running those terrible WR screens for three-yard losses, IMO--they're still kind of a win if your opponent is sitting on those routes, because we're going to be running John Brown behind those opponents in 8 or 10 or 15 more plays.
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