If a "lightfield" is projected into your eye, how do you cope with (additive) light input from the real world? if it is real, will there be a law to tag 'virtu

If a "lightfield" is projected into your eye, how do you cope with (additive) light input from the real world? if it is real, will there be a law to tag 'virtual' things so i don't accidentally kill a real person when I thought that was part of my game? You know how congress or the senate would design that one ;)