The phrase "indisputable proof" means evidence or facts that can't be argued against or questioned. It is evidence that is completely true and cannot be doubted. Full definition
The line of thinking is something like this: (1) contact between players in the box is not automatically a penalty — there has to be sufficient contact in the opinion of the referee — here the contact was trivial; (2) in the absence of indisputable proof of a blatant foul, a referee must take the situation into account; (3) anything short of certainty about a blatant foul should not be a penalty, particularly in the last seconds of a game. (sbnation.com)
Frank AND Chuck are now able to take photographs of key evidence that will provide indisputable proof of Phenotrans» part in the zombie outbreaks, not just in Fortune City, but across the United States. (kotaku.com)
As a closing thought, I leave you with indisputable proof that the Xbox 360 version of Final Fantasy XIII is superior to the PS3 version. (riddlethos.com)