Great topic! I'm going to super blab here so you've been warned!

You make excellent points. I've done lots of research/work in the area of deviant behavior and this is definitely an issue that needs to be addressed. There are many factors that come into place when dealing with any type of predator so it's very difficult to come up with one blanket solution that works for all our states.
Unfortunately, not enough is done to help people before they end up abusing children or adults. But that's another rant for another day!!! There is a high rate of recidivism with sexual predators and that is terribly frightening. There is the ongoing debate of "treating them" or just putting these people through the judicial system. But by the time someone is committing these crimes-the damage is done. Their psyche is tormented and we have victims whose lives have been destroyed.
Then there is the issue with funding the programs that keep track of predators out on probation or parole. This year, over 20,000 sexual offenders were LET OFF OF PROBATION in Arizona because of funding issues (and the fact that there are just not enough people to handle the caseloads-and the fact that AZ cops arrest people if they sneeze on a Tuesday or just walk across the road and even if you didn't do anything wrong they will make it so it looks like you did- but that's another rant for another day!!! And that's not just something AZ does either.) So AZ did it to themselves. Again, another topic. Back to the offenders, so the state simply let them walk. Many offenders are SUPPOSED to let the county/their PO know when they move and usually the neighborhood is informed but many do not and then they are MIA.
You have to remember that sexual offenders do have rights (depends on what state they live in when their civil rights are restored-sometimes not until probation is over etc.) and many feel threatened when they realize that everyone in the neighborhood is watching them. A small price to pay for their crime. Still, you can't harass them and do constant drive-by's because you are suspicious. But what about the offender who was wrongly accused and now is judged by his peers?
So you've got state laws to deal with, budgets, individual rights, different degrees of crimes etc, etc... not to mention all the psychological issues and various societal beliefs/opinions/taboos at hand...oh and as far as I'm concerned the US judicial system is seriously screwed up...so who knows what the answer to this mess is.
I believe that people have the right to know who their neighbors are. Having Internet sites like familywatchdog.com or links from your local government sites are helpful in identifying offenders that live near you. However, rather than spending time freaking out about the possibility of what an offender could do, I believe it's more important to communicate with your children and loved ones about safety and people in general. Just because someone is out on probation and
has registered doesn't mean they won't violate a child or an adult again. Conversely, there is a good chance that another person has learned their lesson and doesn't pose a threat to you, your children or society.
Don't let the government fool you into believing you are safe and don't rely solely on Internet sites for accurate information.
Just because someone shows up on a site as living in your neighborhood doesn't mean that person is a threat. There could be 5 more people living close by who have never been caught who are the biggest threats to your family!
Also, some people are convicted as a felony sexual offender for a crime that probably (depending on what your personal values are) wasn't anything some people would even care about. Say an 18yr old having sex with a 17yr old. If you are convicted then you are in the eyes of the law, a sexual offender. If you'd waited a year then we'd have a totally different story and no offender conviction following you around the rest of your life.
So what is my point?
There are too many variables to worry about. Be aware of who lives around you and take care of your family and your neighbors. Ignorance is not bliss in situations like this. Most importantly, trust your instincts.
I'm glad that you are aware of your surroundings and it's a great thing to learn how your local and state government handle sexual offender cases. The more you understand about predators the more you learn how to arm yourself against those who truly pose a threat to you.
Ultimately, I think it's best to get to know everyone around you. The predators who haven't been caught and the ones who absconded from one state and now live next door to you quite possibly pose and even bigger threat to you. Why? Because they are getting away with it. Now that I've typed that, don't become paranoid about everyone you meet but definitely utilize any available resources to help yourself feel safer in your home.