Nearly everything you read, even from reputable sources, says that before frying or sautéing most foods you should heat the pan before adding oil. And nearly all of those folks say it's because the cooking surface has microscopic pores that close up when heated, ergo less opportunity for sticking. This notion might have been debunked somewhere, but I can't seem to locate it at the moment.
Harold McGee does indeed say to preheat the pan, but that's because "The longer the oil spends in contact with the hot surface, especially metal, the more time it has to be broken down by the extreme conditions and exposure to oxygen. Broken-down oil gets viscous and gummy, and even a slight degree of this can contribute to sticking and residues on the food." However, Kenji López-Alt says, "You may be asking why you can't preheat the pan, then add the oil, and the answer is that you can, technically. The problem is that without oil in it, it's very difficult to determine how hot a pan actually is. Starting with oil in the pan is a good indicator of how hot the pan is. We know that shimmering oil is hotter than pooled oil (it starts shimmering at around 300 to 400°F), while smoking oil is hotter still (depending on the type of oil, this begins at around 450 to 500°F). The oil is a built-in temperature indicator."