As a graduating student of the class of 2006 I would  not have been able to gain the experience that I did without working in a hospitial setting during my externship.  It is also important that people are aware that we as students did not do anything without supervision of a licensed personal, and we always disclose this to the client before doing the procedure needed/recommended.  Therefore I do not feel it is necessary to have a written consent from the person/owner.