We have now a powerful system of display-buffer actions such as
display-buffer-reuse-window, display-buffer-below-selected, etc.
So follow-mode could add a new specific display action to
display-buffer-base-action that will exclude follow-mode windows
from consideration when deciding where to display the buffer.

It doesn't have to exclude all the windows. However, say that we have three side-by-side windows that contains the same buffer and follow-mode is active, then the middle window should not be picked.

-- Anders