A banned user is commiting a Federal crime by accessing a website that they have been banned from.
He is put on notice that he is banned by the website terminating its access ID to post,
as well as other methods such as written notice and/or IP blocking.

The Computer Fraud and Abuse Act of 1986 (CFAA) 18 U.S.C. 1030 is a United States cybersecurity bill that was enacted in 1986 as an amendment to existing computer fraud law.

This law allows Public website owners to have the right to selectively block users from their sites and anyone who intentionally circumvents those blocks may be violating provisions of the CFAA, a federal judge in California ruled in 2013.

The ruling involved a dispute between Craigslist and 3Taps Inc.. Craigslist banned 3Taps, howver 3Taps continued to bypass the blocking methods claiming that Craigslist, by making its website publicly available, had essentially authorized the entire Internet to access and use its content. The company claimed that allowing owners of publicly accessible websites to selectively block individuals and groups was dangerous and contrary to the notion of a free and open Internet..

In a lawsuit filed in the U.S. District Court for the Northern District of California, Craigslist accused 3Taps of "unauthorized access" to its website as defined under the CFAA.

In a 13-page ruling, District Court Judge Charles Breyer dismissed those arguments and held that 3Taps had accessed Craigslist without specific authorization from the website owner.

"The law of trespass on private property provides a useful, if imperfect, analogy," Breyer wrote in his ruling. "Store owners open their doors to the public, but occasionally find it necessary to ban disruptive individuals from the premises. That trespass law has enforced those bans with criminal penalties has not, in the brick and mortar context, resulted in the doomsday scenarios predicted by 3Taps in the Internet context."

Even though Craigslist set up a public website, it was still within its rights to selectively block people it considered undesirable. There is nothing in the CFAA that specifically prohibits websites such as Craigslist from blocking people from their sites on a case-by-case basis, Breyer noted.

The key point to consider was the fact that Craigslist used specific methods to keep 3Taps away, in this case Craiglist used IP Blocking.

It was "a clear signal from the computer owner to the person that he is no longer authorized to access the website," Breyer noted. 3Taps indisputably knew that Craigslist was blocking access its site, but it went ahead anyway by circumventing the barrier Craigslist had in place, he noted.

"The banned user has to follow only one clear rule: do not access the website," Breyer said.

Now you know the law when you get banned from a website.