Well the stun chance is 25%, so it's not terribly likely to happen. But while playtesting I have managed to stun multiple enemies at a time, so it's more a matter of luck I'm afraid.
I made enemies wander mostly because I wanted there to be enemies, but I hate random battle systems. By making them wander players at least have a chance to avoid them. Procrastinator Dave suggested having them drop parts for use in making potions, and I really like that idea so future builds will at least add some incentive to get into scraps with enemies.