Some do, some don't. Some of the Titans themselves don't know how best to use it, because nobody can shoot through the shield some people just abandon their cover to get a shot at enemies.
I run Defender and the people that kill me with a WoD up tend to do it by coming at me from the side or behind, entering the bubble and using melee or a shotgun.
Of course, if I'm not distracted, I can shotgun you as well the second you enter.
I had a funny thing happen where I was playing Control on the Mars map with the Interceptors. I run around a corner and there's an enemy interceptor. I throw up the Ward of Dawn just as he starts firing missiles at me. I guess he thinks the shield only lasts a few seconds or only takes so much damage because he kept trying. So I just started dancing inside the shield as he fired missile after missile at the shield, I was just like "no fucks".
Then he boosted at me while I was dancing and went straight through the bubble and ran me over.