A man who posted a hoax suicide threat on Facebook ending up being arrested and put in a psychiatric institution for nearly three days.
Shane Tusch, 48, a part-time electrician from San Mateo, California, said he wanted to test Facebook's revamped suicide prevention programme.
But after threatening to hang himself from the Golden Gate Bridge, a reader alerted police who then arrested him.
Mr Tusch says he was denied "any humane care" and subjected to medical tests.
Facebook locked his account as well.
Facebook extended its suicide prevention programme in February, enabling concerned readers to flag up posts that indicate someone may be suicidal and get help from trained professionals.
Once alerted, Facebook contacts the potentially suicidal person the next time he or she logs on and offers ways to get help.
Or if Facebook thinks there is an "imminent threat" it may contact local police and ask them to carry out a "welfare check".
'Checks and balances' But Mr Tusch, who is married with two children, said that his experience illustrates the dangers of the social media platform's approach.
"Facebook needs to leave suicide prevention to family and friends," he wrote on his Facebook page.
"There are no checks and balances! I was only proving a point that Facebook should not be involved in this. . . "
The person who flagged up his "suicidal" post was almost "a complete stranger", he maintained.
US lobby group Consumer Watchdog agreed with Mr Tusch's concerns and wrote a letter to Facebook boss Mark Zuckerberg asking him to "suspend the suicide prevention program until it is fully protective of the rights of all individuals and contains safeguards against abuse".
Consumer Watchdog president Jamie Court wrote: "Facebook facilitated this man's loss of freedom for 70 hours and other innocent victims will be caught in Facebook's web if you do not improve the suicide prevention program's procedures."
Mr Tusch says that prior to his fake suicide threat, which used protracted disagreements with his lender Bank of America as a pretext, he had not used Facebook for two years.
Facebook was not immediately available for comment.