How does one just goof a marathon? Particularly when an overwhelming majority of the course is an out-and-back along the river? It's basically impossible to mess this course up: http://www.mapmyrun.com/routes/fullscreen/767059077/
Additionally, if she gave her bib to another woman, that is still cheating. Just last weekend a similar situation happened in the RnR Philly Half w/ a serial cheater having a guy run under her name. However, it would be baffling for someone to run under a purchased bib, b/c this race was still accepting registration the day before the race!! It boggles the mind why someone, particularly someone who would have a legitimate shot at winning a mid-sized race by running a 3:10-11, would buy someone else's bib. Moreover, the race allowed runners to defer to 2016, so even if Ms. Dempsey wasn't feeling up to running yesterday, she could have deferred registration to next year. Clearly, based on athlinks, she runs marathons with relative regularity. The incentive for her to just give away her bib, particularly to someone with high-level local ability, just isn't there.
This is not a "guilty until proven innocent" situation. It's simply looking at a set of data and applying basic common sense. It is impossible, I repeat, impossible, to go from 4:41 in October 2015 to 3:11 in November 2105, even on a nearly pancake flat course in Harrisburg. Claiming this is a rushed conclusion also ignores that nothing in her past results suggest she can run a 7:17 pace for a marathon. Granted, it was in 2009, but her fastest 5K is 23:06, which is 7:26 pace. So again, the ability just does not appear to be there. I would acknowledge her time as a dramatic improvement based on hard work, but her times in all the years succeeding that 5k PR do not suggest much improvement.