I am a graduate student at MIT. I would like to share part of an email that I got from my department.
“We have gotten a report of an incident in the building in which two persons were eating in the same room. Because eating cannot happen with masks on, MIT’s policy is that only one person can eat safely in a room. I appreciate that it can be lonely eating alone but for the safety of all members of the community, please adhere to this policy.”
Right now, the building is operating below capacity, everybody that works on campus (janitors, students, postdocs, faculty, et al.) is tested 1-2 times a week (I know the PCR tests are bogus), and the building in question has a ventilation system.
Another thing is the number of people wearing masks while walking alone or outside (usually I am the only one without one), and parents who have their children wear masks (not all do it, but even a few is concerning to me). This is the institution that, according to QS, is #1 in natural sciences (specifically, #2 in biological sciences).
Although I cannot attest to what is happening at other universities, I would not expect them to be much different, which is probably clear to you already.
A concerned graduate student