Exactly. Some of the pros have developed extremely strong adductor (inner thigh) muscles, and they can get away with having their knees a bit closer to the top tube to enlist those muscles more on the upstroke. However, they won't have any "knee wobble" throughout the pedal stroke. It can be very risky for your knee health to have your knees go out of the centerline when pedaling, either outward or inward. You want your kneecaps to be facing forward. You might be able to accomplish this and have your knees in a bit. It all depends on your own biomechanics. However, I wouldn't really advocate that people change it up just for the sake of enlisting certain muscles or (on the road) to be more aero. If a knee (or both) are out of line, then it could take a negative toll on your knees over time. That's what my orthopedist says and what I've heard from bike fitters.