I don't think anyone can board a plane without wearing a mask, vaccinated or not, but I'm shocked that he was allowed to fly internationally without showing proof of vaccination.
It's his choice not to be vaccinated, of course, but he went for that long shot in the corner pocket and got unlucky when the plane he was on, someone tested positive. If he had been vaccinated, he'd playing in the Mosconi Cup today because he tested negative. Since he was not vaccinated, he's out. Government regulations enforce this. He should have played a safety shot and gotten vaccinated.