The levels of assurance we support are defined here: http://wiki.aaf.edu.au/tech-info/levels-of-assurance
Currently, VH accounts do not go above level 1 in terms of identity assurance. So formally speaking, no ID proofing is necessary. However, we recommend that you go to reasonable lengths to confirm that the user is who they say they are. Practically speaking, VH Administrators generally already know the person by name and on sight, because they are colleagues.
If you do not know the person first hand, you should make a reasonable attempt to verify that they are who they purport to be. This would include cross referencing their details with the organisation's central authority E.g. staff directory, and/or sighting their staff ID.