Hey Ben, sorry this incident got you down but every time something like this happens it just helps drive home that you took the right action with her. You're right, it clearly shows a lack of respect. It's almost like she wanted you to catch her since she was doing this out in the open in your own neighborhood.
It seems VERY suspicious that this was early on a Sunday near your home because A) like you said it sure seems like an overnighter must have happened beforehand and B) since she lives on the other side of town, this implies it was someone she was involved with before moving out. I think you know you deserve better than this and it sounds like you got right back to detachment so that's good!