The short answer is yes (even if this is far less than an ideal outcome). People can and do "fake" being well (e.g. reporting lack of suicidal thoughts or lack of hallucinatory activity). In this manner, they technically are stating that they meet the criteria for discharge, and are, therefore, sometimes discharged despite ongoing risk to themselves. More sophisticated therapists and doctors will often recognize that denial symptoms are operating, and will continue to work with at-risk individual, and not accept his/her concrete statements of safety at face value.
If the hospital team doesn't believe you are well enough to be discharged AND you have been involuntarily committed, then you would not be able to release yourself.
Ghost Adventures - 2008 Former Psychiatric Hospital Northern NJ 1-6 was released on: USA: 21 November 2008 USA: 21 November 2008 USA: 21 November 2008
Combat Hospital - 2011 Reason to Believe 1-10 was released on: USA: 23 August 2011 Hungary: 3 June 2012 Japan: 23 January 2013
Release Yourself was created in 1974.
If you voluntarily admit yourself to a hospital in New York...you become a "guest" of the state for 72 hours. They will evaluate your mental state and either release you, or you stay longer until a doctor says you can be released.
Combat Hospital - 2011 was released on: USA: 2011
Mental Hospital - 1953 was released on: USA: 1953
Doll Hospital - 1952 was released on: USA: 1952
Childrens Hospital - 2008 British Hospital - 4.7 was released on: USA: 20 September 2012
Childrens Hospital - 2008 Home Is Where the Hospital Is - 3.4 was released on: USA: 23 June 2011
A Children's Hospital - 2007 was released on: USA: August 2007
Children's Hospital - 2002 was released on: USA: July 2002
You have to call the hospital, and in a few cases, they will not release this information over the phone.