As I said previously, its like playing Russian Roulette, while it may be mandatory in your mind Dick, in reality, as Capt Midnight says it is not mandatory! Who is right and who is wrong? As Chuck says, airspace built around TCAS. Great safety margin. Passenger safety is being comprised because the whole safety case is based on the lowest common denominator, ie the VFR aircraft.
Ever been into some of these busy CTAF's where you do not get TCAS returns from some light aircraft, is their transponder on or is it u/s. The same can apply in E without radar. The transponder can appear to be operating, but in actual fact if its not no one will know.