It really depends on your program and what university you are at. When people apply for PhD level graduate programs in the US the universities sometimes fund a short list of applicants to fly out and take a look at the program and meet the graduate students over a couple days. This is precisely so the prospective students can get a general sense of how friendly the department is etc. It varies a lot by program and what university you are at - and that is just within a particular field (e.g., a specific field's PhD program).