This surely means that if the aircraft has communicated to the controller and remains on the frequency, the controller has a duty of care to prevent it from running into someone.
Oh Dick trying to draw a long bow again. The phrase
"Radar Service Terminated" is very sufficient in describing that the service has ended; it has been the same phrase for the last 9 years with RIS; why would it suddenly be a problem now? Are you trying to throw in a red herring?
Flight following does not extend sector to sector via the FDP system as it does with IFR in the USA.
Does that make it better? The same phrase "Request handoff for flight following" is used in the USA; this is a request for controllers workload permitting will coordinate to another ATC, In the USA there is no option other than using "the phone" for this transfer of information; why not use an advance system such as TAAATS to help transfer information to another ATC.
UCS RADTAG aint perfect; far from it; but you can use it at certain times perfectly validly. Remember some ATC use it for VFR in class C. FDR is much better as you say, despite what DS thinks; loss of ident (effectively nill lost function) is but one limitation of RADTAGs. That said, if you can use them sucessfully, why not, especially if there's a need to type in the FDR manually or provide no RIS?