Roughly I would say this is not so much a myth, as a test that doesn't preclude it being red book. The display of time between tracks is dependant upon the Q channel subcode. One suspects that this engineer felt that if the CD showed the existence of negative track time subcode information it had been created as a unified compliant disk image.
It is really a matter for the disk master process to decide whether to have the negative count in time codes, or other possibilities with the P&Q codes. There is no mandatory time space between tracks on a CD, you can have as short or as long as you like.
So, if the CD has negative lead-in counts it is almost certainly compliant, because to create them implies the use of a fully red-book aware process. But not having them does not mean you are not compliant.
The night is coming, and its filled with dark surprise.