I have to be honest, setting "do not remember audio" sounds like a decent compromise between not getting anything that you want and getting exactly what you want. It is especially appealing since you get VLC and this compromise solution for free. However if you are still not satisfied:
$ git clone git://git.videolan.org/vlc.git
$ cd vlc
$ ack-grep -r resetVolumeCheckbox ./
$ emacs modules/gui/qt4/components/simple_preferences.cpp
$ git format-patch -o patches origin
$ git send-email --to vlc-devel@videolan.org patches