1) It's all based on speculation by persons not equipped with the experience or the training to make distinctions between a meth lab and your kids science project.
2) There are serious questions of accountability. Now you might think: "Well, if I did nothing wrong then what do I have to hide" but I would like to point out that more than once a little spat between FReepers has turned into posting personal information and attacks. You aren't protected from a vendetta, not even here. So what's to protect you from your postman?
3) There are serious questions about databasing and profiling. Think of the potential for abuse based on these "observations"
4) You can already pick up the phone and call the cops.. And I remember a flight instructor who did exactly that, just to be blown off by the FBI. They drop the ball on an informant's tip, and now they want a tipline to spy on you? Oh right.
5) Any government toy created today will be in the hands of a different administration tomorrow. If you turn dubya loose with this today because you like and trust him then tomorrow it's gonna go to someone else.
I try to not take such a pessimistic view of my neighbors. America pulled together during WWII and endured rationing and neighborhood watch wardens, and enforced blackouts just fine, or so the history so purports since they are no more.