Should security question answers be case-sensitive?

"Security question answers" are akin to auxiliary passwords, which users will not use on a daily basis. Remembering a password that you almost never type is hard. Requiring exact case is likely to make the user fail to answer properly.

On a theoretical point of view, a "security question" is already a huge weakness, which you tolerate because some users will forget their password, and you want to handle that case with as much automation as possible, and not asking any security question would be even worse security-wise. Hence, the added value of security questions is that they allow a not-totally-open password reset process which can nonetheless be conducted automatically, i.e. at minimal cost for the server. Case sensitivity would probably remove much of that value. Actually, I would even recommend normalization by suppressing whitespace, punctuation and accents.