Personally, I think his Pac-Man record was legit, and at least some of his DK records were, as well. It isn't like he actually had opportunity to monkey with the machines before every run he ever did, particularly early on. And he's played live plenty enough times to show he's skilled.
But TG's got their rules, and, while I think they can be exceptional at times about them, it isn't like he didn't know about them. Truthfully, if he'd just come out with a mea culpa, said some stuff about not knowing the machines weren't legit or whatever, they might have just taken the 3 scores down instead of all of his scores. Probably not, but it's certainly possible.
Instead, he had to be his usual douchey self and loudly proclaim that he knew for a fact that the scores were legit, personally watched the PCB get put in the machine, denied he'd ever used MAME, etc.