Mutt: Yes indeed (wherein we've being doing TIBA for years)... that said, one does have to wonder at ones legal position, i.e. when one is issued with a "Radar Service Terminated, continue with TIBA procedures" whilst one is ostensibly operating in accordance with an IFR flight plan (with all the safety elements that IFR entails), and yet one can certainly imagine that, at a subsequent Board of Enquiry, the reason for the 'mid-air collision' would be laid firmly and squarely upon "...the crews failure to maintain adequate separation", or some such phrase.
The bottom line is that, in this day & age, there should be no excuse for operating a Public Transport flight, in a multi-million dollar jet aircraft, packed full of passengers & crew, without the benefit of radar coverage and the constraints of IFR, and especially so in a country supposedly as wealthy as Saudi Arabia !