Personally, I think it would be a very bad idea... For no other reason than the fact that some of these types of events tend to turn violent. Not to say that these will, but the possibility exists. I would tread carefully at any/all events like these, whether carrying or not, if I were to decide to go at all...
So, because "some of these events tend to turn violent" the OP should not open carry? Why, exactly? Not that any of these were violent, BTW.