Part of the nature of a crime is that it's often completely unexpected; no one would imagine someone barging into a home and taking away a child. Now that we have Amber Alerts, at least there is some hope that children can be saved from abductions and that the word will get out more quickly than it did in her case. However, I would only say that it's possible that Richard Allen Davis might have been caught sooner with a better networking system in place. Saying it was fully preventable is likely not so since the crime was completely unexpected, and even with Amber Alerts, people still get abducted.
Polly Klaas's abduction could have been stopped in its tracks most likely. When someone kidnaps a child from a slumber party, something is seriously wrong. Many preventative measures could have and should have been put into place to deter this from happening. It was such a tragedy, and very preventable.
It is so easy to look back and second guess the way the house was locked or not and if this work man who took her should have been watched more carefully or not hired at all. But no one knows every possibility ahead of time and sometimes things happen even when all care is taken.
Well you know, in hindsight we can imagine all the ways that a tragedy could have been prevented. But Polly lived in early 90s Petaluma, California. She was in a safe neighborhood of a safe town, where this sort of thing simply did not happen. There was simply no way to plan for it.
Its sad to say but I do not think there was anything to prevent Polly Klaas' abduction and killing. We learn through trial and error. Criminals spend all their time trying to beat the system, test the fences and figure out a way to not get seen and hopefully not caught. We can always be more aware of our surroundings, but what more do people feel they can do before bed to prevent someone from breaking in when your not expecting it? After all, children get snatched up off bicycles and walking alone on a lonely road, who dares intrude into the home and take off with a child? You don't know to prepare for that until it happens. Just as John Walsh lost his son all those years ago, it was not in vein, Adam Walsh's sad tale reminds us to never let our children out of our site in public, not ever. Now we learn through more elaborate abductions, we arent even safe in our own homes. Polly Klaas' case was a hard reminder that while we sleep these murderers are up scheming and plotting a new way to come after our children.