I agree. Knowing if it came from the street or the bathroom makes a difference in knowing which direction to chase after the person. Or have yourself chased after.
Knowing if it came from the alley or the rooftop would be handy.
I think they do notice it flying into the vicinity before it reaches them depending on their perception. Also, there are other factors to successfully grabbing the item. Timing is one of the things. ;)
I can see other people trying for it and failing get in the way too. Like two baseball players going for the same ball, neither one catches it when individually, both could have.