And where is a character going to learn PrC I would likely only allow the Racial Paragons because those seem not to require training.
Well, according what I read about Knight Protector organization, it is not anysort of organization first of all. It is more of cluster of inviduals who 'long the old days of honor and chivalry' and all follow the Code of Conduct of Knight Protector (which is near identical to Knight's code but it is formed in form of poem). There is no trials of tests, nor admissions nor any mentor relationships, merethat someone declares that he is Knight Proctector and taking the code of conduct behavior is enough to qualify for the PrC.
Also most all Knight Protectors believe to be last remaining members of dying ancient knight order but no one recalls exactly what the order was, but anycase alingment restriction is LG or LN. So many paladins and ex-paladins take path of Knight Proctector.
So I add that my char was raised by the order, or really one member of Knight Proctectors and he had always idealized them and their code but he feels yet unworthy and non-tested yet to declare himself as Knight Proctector (he lacks +8 BAB, Mounted Combat, Cleave and Greater Cleave feats to qualify).
So it could be said my char can be even now be Knight Proctector by name but if he wants to become one, he should follow the codes of chilvary and honor MORE carefully than ordinary knight.