In my experience with mass deafening blindness, they will "see" you if you hit them while deafened most of the time and give chase. This is equally the case with both ranged and melee attacks on them. If however you blind and deafen them and run back without attacking them, they typically don't give chase. So blindness/deafness will by no means make them sit still and beat them to deaf like hold monster or any typical paralyzing agent. Also, when blinded or fighting somebody invisible in the arena, most Players will run around frantically trying to cover ever inch of the ring trying to bump into the mage and attack them via melee, so in defense of the giants, if we do it, why can't they?
Besides, according to most folklore, giants possess some incredible extrasensory abilities, like being able to find out if you're an Englishman by the scent of your blood that's still inside your body. That level of accuracy totally beats drug sniffing dogs, who usually delay my flights because they like my carry-on sandwich.
