"The co-pilot [Andreas Lubitz] of the Germanwings flight that crashed into the French Alps last week had been treated for suicidal tendencies years ago ..." - John Bacon, USA Today, March 30, 2015. Here is the coverage.
Any alert depressive has long known that sharing suicidal thoughts could get you locked up. In many jurisdictions, that's the law. You will be confined against your will in a psychiatric facility, until "they" decide you can be released.
No surprise, those in despair are reluctant to take the first step to seek out some kind of help. Usually, that's by just talking. Opening up can let in the light.
When I had to put my feline companion, Jason, down a few years ago, a smart neighbor warned me, "Don't don't don't say you feel like dying now." Yes yes yes I did feel like dying. She went on to explain that the elderly man a few floors down in our high rise had said a similar thing when his cat died. He had been taken away to Yale Psychiatric Hospital.
Lubitz's crazed act had bundled in too many minds suicidal ideation with homocidal tendencies. Well-meaning citizens could now be scanning the horizon to identify those who might have thoughts of checking out and perceiving it their duty to "turn them in."