I don't think so. The CFAA states:
>Whoever intentionally accesses a computer without authorization or exceeds authorized access, and thereby obtains information from any protected computer shall be punished as provided in subsection (c) of this section. (a)(2)(C)
It defines a "protected computer" as:
>...the term "protected computer" means a computer which is used in or affecting interstate or foreign commerce or communication, including a computer located outside the United States that is used in a manner that affects interstate or foreign commerce or communication of the United States; (e)(2)(B)
As the Supreme Court has ruled that virtually anything in the United States is subject to the Commerce Clause, this comprises practically all computers, especially after you consider that usage of a computer network almost certainly takes your traffic out of state. Many states have corollary laws to the CFAA with substantially similar language, so if you can miraculously convince a judge that the computers involved are not part of interstate commerce and that the feds therefore have no jurisdiction, there's a good chance you'll have to contend against a similarly-worded state statute.
I don't see any limitations or exceptions here. If you are accessing a computer in an "unauthorized" manner and obtain information whilst doing so, you have violated the CFAA.
The reason scraping can happen is a combination of lack of technical awareness (both from lawyers about computers and from programmers about law) and the cost of pursuing a lawsuit. Even if you break the law, someone has to take issue with your law-breaking before anything happens; they have to file either a lawsuit or an indictment to get the ball rolling. That some people are able to get away with violating the CFAA without someone registering a formal complaint on the matter has nothing to do with whether or not one has violated the statute.
The only way that scrapers don't violate the CFAA is a liberal interpretation of the term "unauthorized", wherein a judge states that if a computer is advertising and allowing public access, then all members of the public are inherently authorized to access it. I know that several scrapers have taken their cases through the courts hoping that such an interpretation would be given.