I was referred to a report by Tucson TV station KGUN regarding Pima Community College's response to Loughner's disruptive and threatening behavior. It states that the college's procedures did not include the option of forcing a student to undergo a psychiatric evaluation, which left them no option but to do what they did. However, the report indicates that the University of Arizona, also in Tucson, does have procedures to require those suspected of being a threat due to a mental disorder to undergo a psychiatric evaluation.
The report also indicates that at one point, a campus security officer was asked to remain in the area of a class which Loughner was attending. So, it seems to me that someone must have wondered why the college's procedures did not include an option to have him committed to a mental institution, and that these concerns should have worked their way up to the level of those who create the policies.
This has me wondering once again whether the college had a hidden motive for protecting Loughner from incarceration, such as that he was being used as part of a black operation to do precisely what he ended up doing (but with Giffords dead, to put someone who thinks more like Trump in her place), which is what LaRouche initially suspected. The sheriff's department was apparently familiar with Loughner's case, and it would have known that he had at least one gun.