Board Thread:General Discussion/@comment-71.1.235.131-20171022191243/@comment-27404492-20171022193617

The barrier was designed to protect the audience from getting hit with missed shots. Even if you had a semblance like emeralds, you wouldn't use it on the audience because it wouldn't provide an advantage, so I doubt protection from psychic semblances factored into the design, even if they had some form  of protection. (Which is unlikely)