should they have to prove that their info is included in what's been sold?
Government records like these are an absolute boon to stalkers. Stalking by revenge-minded individuals is a growing problem. I know because I've been stalked, burglarized, vandalized, and generally harassed for 27 years and running.
Privacy out the window. Did I read correctly and see that you have to have a court order to opt out?
This is nothing new. Keep in mind that if you hold or held just about any government or professional licence, your information is public anyway.
In the computer age, there is no hiding. You should simply strive to control the information out there on you by keeping public and private addresses, passwords, emails, and phone numbers. Any form you fill out for anything might eventually be sold or shared with someone, so keep this in mind.
Hint: If you can avoid it, don't put your telephone number on any check you use to pay for something. If the merchant insists, don't give the right number. Otherwise, it'll likely show up on the Web.