And not everything which you might conflict with is fitted with TCAS.
Your just coming in over the north west of scotland inbound to MAN. Just over Lewis you get a cabin pressure failure.
You start your emergency decent all goes well until you have a RA at FL 150 against a Tomcat which is mid exercise on the west coast of Scotland who has just done a pull up from 500ft (opps thats way to low for the yanks say 1500ft) to head off to the fuel bowser. IF your lucky scottish might just see the conflict before the RA but proberly not.
MJ