First, College Ministers need to work with alums because you can help be their bridge to continuous involvement with and commitment to the church. Alums have often called me to ask questions as they worked with the decision of what church to join.
But, more often, alums have called when they were in a situation of controversy within their church. It may be they are just members deciding how to deal with it and sometimes they have been on a key committee such as personnel and wanting guidance. There was the call I got asking if it were normal for a pulpit committee to NOT check any of the references of the person they were recommending as pastor.
Others have called to ask how to find potential staffers and to know if they are presenting themselves honestly, etc. One of our frustrations with Youth Ministers has been their lack of connection to and encouragement to their youth leaving their ministry.....let's not make the same mistake on the other end! Next,reason number 2 to work with alums.