I was next to a large, plastic-looking cone that gives half cover.
A Cultist ran up alongside my cover causing my Assault rifle to gain a massive penalty.
I figured I'd switch to hand-to-hand and punch him, but it said "You cannot attack through cover."
So, I figured I'd step over to another large, plastic-looking cone and shoot the man.
Moving away from the Cultist told me there was a 10% chance of an AoO.
I moved and it didn't trigger.
Might be an idea to see if this can trigger and whether it causes any problems with not normally being allowed to attack through cover.