Oh, I dunno. I think Imus marches to his own drummer. I don't listen to Imus much because I don't find his schtick entertaining. I believe that Imus chose the direction of this morning's interview, and isn't amenable to direction from his guests.
I do agree with the speculation that Kerry will either deny or "no comment" the story. My intuition is that one object of the media and DNC is to paint this as an RNC-planted story, and another object is to paint any person who is taken aback by the story as a busybody.