Our Government already has a system in place very similar to Amber Alert. The authorities can very quickly get information to Air and Sea Ports, CCTV operators, news and radio stations - which is essentially what Amber Alert is. Why should they spend money on Amber Alert when we already have an excellent system in place.
Amber Alert in the US has been criticised because in some cases the abductor panics when he hears the Amber Alert and disposes of the child in the most terrible way. It's not a solve all for abduction cases and it won't do anything to get Maddie back, it's only useful in the few hours immediately after the abduction takes place.
A far better way of ensuring children are safe is to ensure they are properly supervised at all times that way you won't have to rely on any system to get your children back safely.