I recently went for a second look. I went with the idea of just letting the program know that I was very interested, and also to have a chance to talk to a few more of the residents and also see the OR. I was lucky enough to run into one of the attendings who I had previously interviewed with, and then stopped by the PD's office to say hello. She was very friendly, and actually sat down to talk with me about my plans for the match. She also inquired about my intern plans, and offered her opinion on the programs I had interviewed at. All in all, I feel very glad that I went, even though it involved travel and airfare... but, this program is a clear front runner for my rank list, and as I see it, every little bit helps.
Good luck
John