Not for one minute would I say hanging a banner up will make a non singing fan sing. Only a fan can make him or her want to sing. What a banner does do is create a better look and atmosphere for the singers to be in.
Even though we stand in 115, safestanding being introduced will give it the push to get more like minded fans to group up and move to the singing area.
A lot has been done to encourage a singing section, but you cant force singers to move in and the people there cant be forced to sing they need to want to. When Ageuro scores 2,000 fans sing "Sergio, Sergio". So after that the fans don't get replaced by tourists or not sing because of expensive beer or whatever other excuse there is, they just stop singing and leave it to the 150 or so of us that do.
But for the singers, let us hang some banners up.