Actually just finished interviewing today.
I lost track of all the illegal questions/potential match violations I encountered. Most were innocuous, some where just flat out weird.
-Being asked if I applied to X program also?
-Being asked how I liked X program compared to Y (program I was interviewing at)?
-Being asked where the dinner was for X program?
-Being asked if I had a family? (I suppose they meant wife and kids, but I'm not exactly an orphan)
-Being told about which beaches had the prettiest girls by an 70+ y/o radiologist (not a match violation, just awkward) when discussing the area.
-Being asked why I wouldn't want to stay at my home program?
-Being asked where I was flying to next (subtle, but some destinations give away programs. No one goes for Rochester, MN for fun)
-Being asked what country I'm from (...my place of birth is listed on the ERAS application, and it's the US).