so might not have noticed her coming back in. When I ran the 1/2 marathon last summer, at the beginning it was a giant pack. In the middle I was running with mostly the same people. By the end a lot of people were slowing down, getting cramps, etc., so it was all new faces. Plus, a bunch of 5K people had their race over part of the same course, so it was impossible to tell which race these people were running just by looking at them. I imagine it could be the same way at other 1/2 marathons.