One of the questions on the alias today was "How to automatically populate the comments section"
Ed Hintz (of the MSSCI provider fame) posted this code as a sample:
m_pendingCheckin = pendingCheckin;
// Code to get list of checked pending changes from m_pendingCheckin and
// extract tagged comments string would need to be placed here
m_pendingCheckin.PendingChanges.Comment = “Your extracted tagged comments go here”;
Brian pointed this checkin policy is evaluated many times so buyer beware to perf impact