Yes it is one of those things in hindsight you smack your forehead over and say how could I have been so stupid
I did consider doing it at the time, but because it is quite a bit of extra work I took a shortcut and thought that per library settings would be enough. Obviously it isn't... duh... I only use a single list myself so hadn't spotted the impact of it in usage.
I'm coding it up at the moment so should be a release in a few hours.