The latest security alert from UCPD advises students to “Avoid isolated bus or train stops, especially at times when few other people are around.” A few parts to this.
All train stops serving the University are isolated. The CTA Green and Red Line stops all sit west of Washington Park, which as noted is beyond range of UCPD operations. Metra trains stop closer to campus but, elevated and fenced off, are less visible from the street and typically darker than CTA stations.
All bus stops are isolated, or as good as isolated. To the extent that even sheltered (or canopied) stops are open air and ungated, all bus stops are exposed to all means of street traffic irrespective of their location.
Bus and train stops are routinely depopulated by busses and trains. After each pickup and drop off, busses and trains leave few people waiting around stops. This is how public transit works.
There is no accurate means of gauging appropriate times for the presence of other people. Someone will always be the first person at the stop. Often, that person will be the only person at the stop.
Considering which it’s hard not to read the tip as inducement to stay home in Hyde Park.