TWR INSTRUCTED ANOTHER ACFT TO CROSS RWY IN FRONT OF RPTR ROLLING OUT AFTER LNDG. RPTR QUESTIONED TWR ABOUT THEIR TECHNIQUE DURING TAXI TO PARKING; RESULTING IN LACK OF TAXI TO PARKING INSTRUCTIONS FROM GND CTL.

Narrative

DURING ROLLOUT ON RWY 12L AT STL THE LCL CTLR INSTRUCTED US TO 'EXIT AT TXWY H; COMPANY XING DOWNFIELD.' THIS INSTRUCTION WAS ISSUED TO US WHILE WE WERE STILL ROLLING AT ABOUT 100-80 KTS AND SUBSEQUENTLY I SAW A B727 XING FROM L TO R MOVING INTO THE NO TRANSGRESSION ZONE. I ASKED THE CAPT WHAT GIVES THE TWR THE RIGHT TO CROSS TFC WITHOUT OUR COMMITMENT TO MAKE TXWY H. THE CAPT ASKED THE TWR WHAT IF ANY EQUIP THEY HAD THAT PROVIDES THEM THE ABILITY TO DETERMINE WHETHER WE WOULD BE ABLE TO ACTUALLY MAKE TXWY H SINCE WE DID NOT CONFIRM THE ABILITY TO EXIT AT TXWY H. THE TWR RESPONSE WAS THAT THEY DID NOT EVEN REQUIRE A RESPONSE FROM US. FROM THAT POINT ON; THE CAPT AND THE TWR DISCUSSED IT UNTIL THE CAPT HAD TAXIED THE ACFT ONTO THE COMPANY RAMP. I ASKED THE CAPT WHETHER WE SHOULD CONTACT GND TO OBTAIN A LATE CLRNC FROM THE RWY TO THE RAMP; A DISTANCE OF ABOUT 500 FT; AND HE STATED THAT SINCE HE WAS IN CONTACT WITH THE TWR TO JUST CALL RAMP CTL AND FORGET GND. UPON ARR AT THE GATE; THE CAPT CALLED THE TWR AND INITIALLY TALKED TO THE LCL CTLR THAT APPEARED APOLOGETIC BUT SINCE THEY WERE NOT ABLE TO COME TO AN AGREEMENT OF WHAT WAS THE PROPER PROC; THE CAPT TALKED WITH THE TWR SUPVR. THE TWR SUPVR DENIED THE ACFT WAS ON THE RWY; BUT WHAT I SAW WAS THE B727 STARTING TO MOVE AND ENTER THE SAFETY ZONE (BEYOND THE HOLD SHORT LINES) WHILE WE WERE STILL ON THE CTRLINE OF THE RWY. IN ADDITION; THE TWR SUPVR STATED THAT THEY ARE ABLE TO ISSUE THE ABOVE INSTRUCTIONS WHEN THE TWR SEES THAT WE HAVE SLOWED THE ACFT TO TAXI SPD; THEN THEY HAVE THE RIGHT TO CROSS TFC. I DO NOT BELIEVE THAT THIS IS CORRECT!!! IF I HAD TO DO IT OVER AGAIN; I BELIEVE THAT I WOULD HAVE CALLED GND ANYWAY EVEN THOUGH WE WERE ALREADY ON THE COMPANY RAMP. PLEASE KEEP IN MIND THAT WHEN AN ACFT STARTS TO CLR THE RWY; THE ACFT HAS TO BE RECONFIGURED AND THAT IS USUALLY DONE BY THE COPLT. WHEN THE COPLT IS THE ONE THAT JUST LANDED THE ACFT; THERE IS ALSO THE TRANSITION TIME TO BE CONSIDERED. BY THE TIME THE ABOVE DUTIES ARE ACCOMPLISHED; THE ACFT COULD WELL HAVE TRAVELED 500 FT IF THE CAPT DOES NOT STOP THE ACFT WHEN CLRING THE RWY TO CONTACT GND CTL.