To add on to Wisco1's comment, just working here I can tell you that for every 1 person who knows someone at Mayo, works at Mayo, or who has a parent that's a consultant here that gets accepted to MMS there are probably 50 others that have those same supposed ins who don't get accepted. I'm not exaggerating much either. Mayo has over 30,000 employees. There are a lot of people here who think that coming here to work under a Mayo researcher, having a consultant parent, coming here to do a SURF, or whatever else will get them in the doorway to the med school here and for most that isn't the case. There are just too many of them and there are other criteria Mayo seems to definitely be looking for.
That said, just like anywhere else, all other things being equal having a really strong rec from someone the adcom members know and trust probably does carry a little more weight than a really strong rec from someone on the other side of the country they've never met before. In fairness, there was a student survey done on schools by the AAMC and some comments were made about legacy students by current Mayo students. So yeah, realistically there probably is a little bit of that going on, but there's also probably a lot of confirmation bias going on as well in reaching that conclusion. You know about that one guy who did research with that big cheese who got in when you didn't, but you don't know about those other 100 guys who did research with those other big cheeses who didn't get in.
