IMO, the wearing of blackface does not ipso facto constitute "mocking" black persons.  I think intent is important...We've just seen this with the furor over the actions of Ms. Shurtz.

However, in today's very divisive climate, the action of wearing of "blackface" is likely to cause problems for everyone involved as it will be far more likely seen as a "mocking" action than an "honoring" action.  Unfortunately, it is also far more likely that it will be a "mocking" behavior rather than an "honoring" behavior.  I think Ms Shurtz's case is clearly the exception.....