Most meander home at odd hours of the night, and barely make it to class come Monday morning. But not everyone does. Some are forced to stay home and nurse their aching heads and soothe their riotous stomachs. Still others are addicted. The University is what a social worker might call a giant enabler.
Intervention is necessary to protect the health of the afflicted and preserve the safety of others.
Privacy invasions exist on a continuum. There is a huge difference between taking pictures of someone through their bathroom window, and intervening to seek help for someone who needs it. Suppose your best friend confessed suicidal intentions in confidence. I should hope so. The comfort of privacy should never outweigh the value of human life.