I wore Smith Optics Aegis (notice the past tense there) and I always noticed a little extra space between my face and the lens at the bottom, enough that a bb COULD go through, theoretically, but put that in the back of my mind and played on. Seemed like a real freak shot to get it in there, unless for some reason I looked up while getting shot at, which seemed unlikely outdoors.
Definitely going to switch out now though, only realizing it the danger after it unfortunately happened to someone else.
Hack, have you looked at goggles with fans? I myself haven't gotten a pair yet, but I think I will soon.