Quinlan does hide his presence from a Jedi (Kruuhk or however you spell it) while masquarading as a Sith. He becomes invisible and walks past the Jedi, only to be caught out when Kruuhk smells the ozone when Vos turns his lightsaber on. It is most probably this is the same ability Tholme has, being his master.
However this would just be Lucas covering up for adding in a new Jedi character and not considering the circumstances it would evoke. By the time TPM was filmed, that was not Quinlan Vos in TPM, but just an extra in the film. Some writer created the Vos character, inspired by this extra. Thus the extra becomes Quinlan Vos.