I once saw Heston Blumenthal, one of the chefs reputed for his "molecular gastronomy" approach, claim in one of his television shows that it made a difference to the pasta whether you lifted it out of the pan with a "spaghetti claw", or tipped the panful water and all into a colander to drain. He claimed that if you lifted the spaghetti out of the water some starchy component in the water tended to readhere to the surface of the pasta due to surface effects, so it was better to drain it in a colander. I have been unable to track down a reference for this, though if you look for his recipes on the web they do instruct draining in a colander, if they specify any draining method.
I can understand that if you did have a layer of, say, soot lying on the surface of the water, a surface effect would apply and lifting the pasta out of the water would make the soot stick to the pasta to a greater extent that if you tipped it into a colander to drain, where probably a greater part of the soot would remain on the interior of the pan.
But what can be in, or on the surface of, pasta-cooking water that would behave like soot here? And why would you want to avoid it sticking to the surface of the pasta?