Not really
Well, I searched the forum on A319. In the long thread on the introduction of the A319 by EZY, the existence of the extra exits is mentioned, but not why. There is a suggestion that they may be required by law. Is this actually the case, or just speculation?
(I note that Swiss is now adding rows in all A32x aircraft. For the A319, I am interested in knowing whether this would require them legally to add emergency exits.)
Momo