Isn't banning lurkers a bit like restricting a theater to only the
actors?   You may feel "uncomfortable dancing around on a stage with
silent gawkers", but isn't that better than a bunch of empty seats.
At least they're not "BOOing".

How else would I be exposed to such profoundities as "during WW2 my
astigmatic grandmother was employed calibrating crosshairs on
periscopes."   (To which I have no real compulsion to respond.)

RevRhodes