To respond to Christian Gerike-
 
In my experience, engineering students and medical students do indeed
deal with real situations through internships, residencies, etc.  At
some point your have to stop reading about "it" and actually do "it".
 
Field school, IMHO, should be where the theory provided in the classroom
encounters the real world of practice.  Mock sites have many merits, but
so do real sites.
 
I will be the first to admit that real sites impose a considerable
burden in terms of development of research designs, artifact and data
processing, curation, and reporting - but these are nothing new to
archaeology, and if one was doing the mock site as a complete
representation of the archaeological research process, these elements
would be present there as well.
 
John
 
John P. McCarthy, SOPA
Sr. Research Fellow, Institute for Minnesota Archaeology
Vice President, Sr. Archaeologist/Historian, IMA Consulting, Inc.
Minneapolis