I’m not sure I understand your question, but anyway I went to grad school in an urban area of a major city and there were no ID checks during business hours, i.e. when classes were held. There was security to keep thieves and other ne’er-do-wells out but not to keep people from auditing classes.
In theory you did need ID to get into the libraries but that could be easily circumvented—apparently if the library has government documents they cannot deny entry to the general public.
I’m not sure I understand your question, but anyway I went to grad school in an urban area of a major city and there were no ID checks during business hours, i.e. when classes were held. There was security to keep thieves and other ne’er-do-wells out but not to keep people from auditing classes.
In theory you did need ID to get into the libraries but that could be easily circumvented—apparently if the library has government documents they cannot deny entry to the general public.