As in many things, I am of two minds here. Yes, it is getting rather crowded inside my skull

On the one hand, I think anyone using a realistic-looking weapon in a threatening manner deserves to have others treat them as a legitimate threat and act accordingly. I've spent my life around firearms, and I am not the least bit confident that if I see someone step out of an alley and point a firearm-ish looking thing at me, I will be able to instantaneously and accurately tell the difference. I'll react as if the threat is real and take the consequences if it was someone's bad idea of a prank.
On the other hand, I have never understood the fascination with making toys look real. Toy guns are toy guns. If you want something that looks like a real gun, then buy a real gun! Airsoft does have some practical application in firearms training, but there are also practical ways to use real guns, which are more effective.
Honestly, I'm surprised that more crimes aren't committed with look-alikes. Seems like the way to go, especially considering that if you get caught (but not killed), the penalties are lower than if you had done the same thing with a firearm.