One of the deep concerns of officers is mistaking a toy gun for a real gun and shooting a child. This is a serious and real problem as toy guns look more and more like real guns. And real guns are looking more and more like toy guns.
This NPR story points out the challenges of this problem.
http://www.npr.org/player/embed/486057234/486646259
The article points out that officers in Baltimore picked up a mix of toy and real guns in a raid including a pink rifle. I easily found this photo of a rifle for sale on the Internet.
See the problem?