<sigh>... that's why I said I am moving to your building! LOL. Quality of the board members really makes a big different... knowledgeable and professionals like people from this group is really admirable.
(1) We have cross-over issues all the time. We always give notice.
(2) If one unit complains that they have no hot water, we do check the surrounding units, up, down, next door. We always give notice.