Guys, my two main points are that there is almost certainly some level of health danger in being exposed to smoke oil. As for how bad the oil is or how much exposure we get, that is open to discusssion. I do know that the labels of many oils say to avoid prolonged exposure on your skin or in breathing. Now the oil may often be diluted when it reaches the crowd or often blow downwind, but not always.
Let's say you went to a play about the attack on the Polesti refinery and they had actual oil fires burning inside the theater or you went to a play about the 9-11 collapse of the world trade center buildings,and they had actual clouds of dust all over you ,just like the real thing. Would this be ok, would you want your children to breathe and be exposed to it? Would you like to take your kids or yourself to one of those Vegas casinos that are thick with cigarette smoke?Of course not.
So if the airshow or acro act wants to use smoke oil, they ought to have the warning as part of their pre sho notice to the public. Then let the public decide it they want to stand there and breathe it.
And of course as BRP says we don't really need to have smoke oil to have a show or an acro act. If you go to some states and some big cities, there are so many billboards that they almost block the sky. But here there are laws against such billboards and free standing signs. So no business has them, no one is at a disadvantage, no one needs to make such a standout.
We can certainly have good airshows without smoke oil, and it will be better for our health and for the environment.