[Superman]

Well, the simpler it is to administer then the less gubmint regulation and cost you are requesting. And maybe it could be done with just a few additional resources. But make no mistake about it, resources will be expended to initiate and administer this. If it is states that keep these lists, then.....

* What states do not? (there are probably some who do not, then one question that pops up is whether sex offnders can get Viagra in those states....I guess the answer is "yes" unless you give those states some money to get in the game of compiling and maintaining lists)
* Are states definitions of "sex offender" all the same? My guess is "no." If my guess is correct, then you'll be administering this program to apples in one state, and oranges in another. Clearly unlawful to do that.
* How will these states share information? Are their computer systems compatible?
* Who will compile the Federal (rollup) version of this list. What gubmint agency?

*Where will the funds for this come from?