CAS is a voluntary agreement between the major US ISPs and the copyright holders. The principle is fairly simple: the internet will be monitored for P2P filesharers. Where those users are deemed to be sharing copyrighted material, the ISPs will be notified. The major ISPs have then agreed to ‘warn’ the user to stop breaching copyright. The nature of the warning will increase each time to a maximum of six warnings – hence the common term ‘six strikes.’
Since it is a voluntary agreement, the only known details are those that have been voluntarily shared, or leaked. TorrentFreak reports that “AT&T will block users’ access to some of the most frequently visited websites on the Internet... Verizon will slow down the connection speeds of repeated pirates, and Time Warner Cable will temporarily interrupt people’s ability to browse the Internet.” It is not known what will happen after six warnings have been delivered to repeat offenders, although it is considered likely that the ISPs will provide the copyright holders with the user details to facilitate prosecution.
The system is heavily criticized. EFF worries that the CAS website, operated by the Center for Copyright Information (CCI) is full of erroneous material. CCI says, for example, “Subscribers are responsible for making sure their Internet account is not used for copyright infringement.” Not so, says EFF, “at least not under copyright law, unless additional conditions are met.” EFF, and many other critics, are concerned that the process “seems designed to undermine the open Wi-Fi movement, even though open wireless is widely recognized to be tremendously beneficial to the public.”
Letting guests and even the general public use your spare capacity is considered by many to be a social service. Bruce Schneier once wrote, “Anyone with wireless capability who can see my network can use it to access the internet. To me, it's basic politeness. Providing internet access to guests is kind of like providing... a hot cup of tea.” But since only the IP address is monitored, it is the subscriber rather the the infringer who will be warned.
Other critics warn that monitoring is easy to bypass with VPNs and proxies and simply changing to a non-participating ISP. Stun has published the #Anonymous Guide to Fighting the MAFIAA™ [Music And Film Industry Association of America™] Six Strikes. The Daily Dot suggests that since internet cafés will not be included in CAS, “Places like cafés and bars with open WiFi might become the new havens for pirates.” But if CAS doesn’t work (in France, the three strike HADOPI system reduced piracy but did not increase music sales), MAFIAA™’s response will probably be to ratchet up rather than back off. “It’s not at all unreasonable to think that the sanctions could get more Draconian, given Hollywood's well-known history of pushing for ever-stronger restrictions once the camel's nose is under the tent,” warns ReadWrite.