In order to minimize risk both to the university and to the international person seeking placement, the UCSF policy is that individuals holding non-immigrant visa status, including individuals on visitor visas, can NOT volunteer at UCSF (see Campus Administrative Policies 100-15 International Students and Scholars, III. Policy, section I, at http://policies.ucsf.edu/)
The main issue regarding volunteering by individuals holding non-immigrant visas is how to define employment versus volunteering. Not surprisingly, this differentiation is not easy or clear. Generally speaking, international scholars/visitors can provide "volunteer" services only for "civic, charitable, or humanitarian" purposes. Hence "volunteering" in a research laboratory, patient clinics, academic or clinical departments, or most other parts of UCSF, generally would not qualify under such criteria.
The consequence of wrongly classifying an individual as a "volunteer" could lead to an audit by the Department of Homeland Security and/or the Department of Labor. If the volunteer activity is classified as work by the auditing agency, UCSF would be liable for all back wages, federal and state fines for violating wage and hour laws, and potential loss of federal research grants (see Executive Order 12989). A non-immigrant found to be working without proper authorization is in violation of federal immigration and labor laws.
Please note that there are always ways to properly appoint an international scholar at UCSF using an appropriate visa category with UCSF sponsorship, even without a salary.
Any questions related to this topic should be sent to Brian Groves, Director, International Students and Scholars Office at firstname.lastname@example.org.