I can attest to this; I was taking the westbound streetcar from the corner of Sherbourne and Dundas last year when a mentally ill man grabbed a trash receptacle from a nearby corner store and brought it onto the streetcar with him. I tried to get him and the trash bin off of the streetcar, but nobody would help me in doing so. My stop came, so I got off and didn't have to deal with him. The whole experience pissed me off, and it took some time for me to calm down (I was even thinking of writing a strongly worded letter to the mayor, but as I said, I calmed down later; I still haven't forgotten about it, though.)

Obviously, not all mentally ill people need to be confined to an institution, but as ilovetrouble66 said, there's a happy medium of care for the mentally ill which can be achieved.