Since ID's cannot be blocked when the recipient is an 800 number, they allow their clients to forward incoming calls to their service. The caller ID info is then collected and forwarded along with the call, back to their clients.
Advocacy groups for victims of domestic violence are concerned.
Victims of annoying calls hiding behind caller ID blocking rejoice.
Article can be found here http://blog.wired.com/27bstroke6/2009/02/trapcall.html. Discuss among yourselves.