Originally Posted by
Tzardok
I'm not sure how you came up with that. A tower shield can explicitely be used to grant the wielder total cover, thereby breaking line of effect (with the special exception for targetting spells. So it can't hide you from, for example, a magic missile, but it blocks explosion type effects). And gaze attacks follow line of sight, not line of effect. Concealment defends against it, but cover not (unless it is opaque).