NY also fills its slots—mostly lottery and their race always has a higher percentage of starters (and finishers) and we know that race ain't cheap—we saw what they're charging this year. Why is that? Is it because NY is a more attractive or compelling destination? More int'l runners? I've run them both— several times—and logistically and economically, Chicago is way easier to manage. Crowds, accommodations, easy flights, good weather, flat course—all favor Chicago. Maybe more newbies run Chicago and tend to drop before race day. Maybe more charity runners in Chicago who are not up for the task of 26.2 after all? Allowing transfers would certainly help the percentages, but then the race could sell out in a heartbeat— everyone would sign up knowing they have an 'out'. It's a toughie—those empty slots indeed would easily be absorbed with those who got locked out.