@LakeWashington, legally, maybe a college could ban certain clothing (including the masks). The KKK cases involve state laws, and I don’t know off the top of my head whether the US Sup Ct. has ever addressed the question directly. But if memory serves, the rationale is that the mask has independant significance as a threat. So yeah, the “antifa” knuckleheads are certainly open to a somewhat similar argument. But politically? There is no way a college would even dare think of doing that, even assuming they weren’t generally sympathetic to the little fascists.
State laws appear to be all over the place on the mask banning issue. Alabama has a broad anti-mask law so Auburn University had standing to have police order the removal of masks at a recent protest. DC also has a broad anti-mask law as does NY which allowed police to order removal during the Occupy Wall Street movement.
Believe it or not Berkeley actually has a policy that prohibits masks being worn by “individuals who are not affiliated with the university for the purpose of intimidation.”
Here’s a recent NY Times article addressing the issue of masks:
https://www.nytimes.com/2017/04/26/us/protests-masks-laws.html?mcubz=0