Is it common to perform a campus interview before asking for letters of recommendation I was recently invited to an on-campus interview after having a skype interview. I noticed, after checking with my referees, that this particular school did not request letters of recommendation for me. It just seems odd to me that the search committee would commit to flying me out and having me complete two full days of interviews without first reviewing letters of rec. 

Is this unusual? What would the advantages of doing the interview before reviewing letters be?
I think they will ask for the recommendation letters at a later stage. It seems to me that they first want to interview you.