Mikey, don't get too het-up right now, the law in itself can only touch us if imitation firearms are banned, and then you'll have tons of people going mental about it (Kids that own water pistols for a start!)
A piece of wood carved into the shape of a pistol is an imitation firearm, seriously!...All it does is facilitate the arrest of someone acting in a suspicious manner with one of these things. What we ARE at risk of, is an overzealous, potentially fascist police officer who wants to use the law as an excuse to use his power over someone.
It's not the law that affects us, it's the interpretation of that law. When a police officer arrests someone he has to arrest them under a charge which is a recognised law. In this case there are a number of laws that could be used "Behaviour likely to cause a breach of the peace", "Common assault", "Reckless endangerment" (I think)...possession of an imitation firearm, however, is quite a strong charge I believe, in order to be able to bang this guy up for longer (Thank god!)
As long as we act responsibly and keep the public informed, "Possession of an imitation firearm" is never likely to affect us, unless you encounter a particularly unpleasant copper...but even then, it's no different to anything else he could do to you...you could get nicked for telling someone to "F*** off" (Common assault)...
It's all subjective really