Yea, good idea. Would be 1 more switch in /window:
/window -yNM
if N = 0 remove scrollbar(s)
if N = 1 set scrollbar(s)
if M = 1 vertical scrollbar
if M = 2 horizontal scrollbar
if M = 3 vertical & horizontal scrollbar
example:
/window -y01- remove vertical scrollbar
/window -y11- set vertical scrollbar
/window -y03- remove both vertical & horizontal scrollbars
/window -y13- set vertical & horizontal scrollbars