Do we know if she even had her pocketbook when the bank's cameras caught her if they did?
She might not have, Morgan hitchhiking on Copeley Rd is the last sighting of her around 9:30pm.
I don't see how someone couldn't notice that they dropped their pocketbook unless they were completely wasted. She knew where JPJ arena was so she couldn't have been that wasted. She was also doing a lot of walking around so if she had drank, she would sober up a little. We don't have witnesses saying she was falling over drunk or drunk and sloppy, so i take it if she did drink, it wasn't much at all. With her size, if she did get drunk, i would think it would be noticeable. She's a small girl and alcohol effects them stronger.
She could have tossed her pocketbook on purpose to mark where she had been if something was wrong. If you look at a map, where the purse was found and also where sighting #5 is, it looks very isolated it's a grassy area near the track that borders trees almost parallel to Copeley Rd and facing the back of the Ivy Rd Shopping center (as if she was going to cut through the little bit of trees woods, then the traintracks, to the back of the shopping center.
Why would she go all the way out there that far away from the arena and her friend and car, by herself? It's very strange.. If at some point she sensed that someone was stalking her maybe she tried to flee him. If she thought something bad might happen to herself, she could have ditched the purse to leave a trail?
If the video at the bank shows her with her pocketbook getting into a vehicle, i'd say the perp is the one who ditched it.
http://www.roanoke.com/datasphere/wb/xp-224154
(Above link has a map, you have to scroll down. You can also move the map around with your mouse to see where sighting #6 on the bridge was)