I don't think tossing the cellphone and bag out the window along a fairly busy road necessarily indicates a disorganised perp.
An organised perp may well have rehearsed the most efficient way to conduct the abduction, including tossing practise items out the window (ordinary sorts of trash items that wouldn't draw undue attention if found, such as partially full water bottle). They'd have a checklist of tasks and what order to accomplish them.
If you consider that escape is among the priorities of an organised perp, then tossing the cellphone and bag was certainly effective in accomplishing it.
I'm not saying that either. I am saying the motivation for tossing the items where they were found depends on whether it is an organized or disorganized killer.