http://www.ncbi.nlm.nih.gov/pubmed/18765703
http://www.ncbi.nlm.nih.gov/pubmed/20042833
http://content.nejm.org/cgi/content/full/353/11/1085
Medical student health is a huge concern and there's much much more data out there. Look for yourselves next time.
Fine, realistic. But I'll say it again, medical school is very difficult and it will be even more tortuous if you're not happy where you are. This can also have a huge impact on your performance as well. Sure, you can find a thing or two you love about a particular school, but these are simply compensatory self-justifications at best if you're not truly happy in the grand scheme.
But I do agree with you that it is still difficult to fully assess whether a place is a right fit for you based on one or two visits, however, it's the best method by which one has to go on at the moment.
In the end, I don't think it's so unreasonable for someone to turn down multiple acceptances and then reapply if he/she feels that they can do better the next time around and be happier in the long run. Some well-qualified applicants will think of doing this at one point or another. It's usually the less accomplished applicants that chastise them to no end, maybe because they don't have the luxury of having confidence in reapplying and will take the first acceptance they get (Note: don't read anything personal into this, I don't care what kind of applicant you are or what your stats are).