On the handbook page directly under the program information is an indication as to whether or not a program wants to be contacted by students. If a program indicates “no”, do not contact them unless they contact you first.
This field in the handbook is the result of feedback from the programs about student contact. If they have indicated “no”, you cannot contact for any reason during rounds or otherwise. This means that you must choose your designation months carefully. If you apply for the same month for all your top programs, you may find yourself with the tough choice of picking only one program. Please designate carefully so that you can spread out your offers and get hopefully all your top programs.