So far, I have only ever encountered two people whom I have told who I feel had the right to know about me and diapers; both are related to rooming in college.
The first is the first guy I intended to room with next year. We were already good friends, but I felt obligated to tell him so he could decide if he wanted to put of with the potential issue.
The second is the leader of the suite I am moving into next year. He invited me to be in the suite months ago, and I told him after everything was finalized. I felt obligated to tell him because I felt he should have knowledge of anything that might cause an issue so that he could approach me without awkwardness.
I generally believe that the person who's room you intend to live in should know, so that they have fair warning.
What do you guys think?