Short and to the point:
Never trust anyone other than your own wisdom ever. Strive to attain it and diagnose egoistic inner voice from purer wisdom obtained through whatever spiritual/social service type disciplines you practice.Have humility and always keep this in mind that you can be wrong and the other as right without being low in self respect/confidence.
As far as claims of various people are concerned, I don't comment without personally meeting somebody or knowing their thoughts by reading them at least. In case of Dada Lekhraj, I am quite sure that he was not what he is made out to be by BK PR agencies.
In case of any other god-man, well, if one can be wrong so can the others.