While I agree that simply imprisoning someone in mental crisis is wrong, assuming a person experiencing a psychotic episode will just sit back and voluntarily check into a hospital or even just pop a pill is also kind of a far-fetched idea.
I know when I was deep in psychosis, I didn't think any of my thinking was out of place because what I was thinking was my reality or at least my perception of reality. Since I didn't know or think I was psychotic, why would I take meds? Why would I even go to see a psychiatrist or check in to inpatient treatment? Do you catch what I'm saying?
Like
@deficiT said, sometimes an intervention of some sort is necessary to persuade an individual that no, they are not being followed by CIA or that cameras and microphones are installed all over the place. But when you thinks it's real, voluntary is sometimes a tall order. Like I said, outright imprisonment is wrong but sometimes creative solutions are needed that don't involve imprisonment of course.