No offense, but this is probably one of the silliest (and possibly most dangerous) ideas that I have heard.
We are always told that if you ever need to draw your gun on someone, make sure you are 100% prepared to pull the trigger. Why is this? Because you are essentially forcing the attacker/intruder to make a decision - fight or flight. If they decide to flee - fine. But if they decide to attack you need to make sure can do what you need to stop them. An airsoft gun does not have the capability to do this, and the fact that they do look like real guns can only make the situation worse if the attacker is armed. In a situation where they attacker may have just been after your physical possessions (and no, I am not advocating anyone simply roll over if they are ever confronted by a criminal provided they have the means to stop them), you are now forcing them to make a choice, one of which is to cause you physical harm - perhaps lethal. If they had a real gun or even a knife you'd likely be on the losing end, and there really is no way for you to know for sure whether or not they are armed until it is too late.
Rocko