BBC web site...
The records could potentially reveal the whereabouts of individuals whose remains were never found, or never identified. Grave after grave in the World War I cemeteries mark the last resting place of an unknown soldier.
Do not get carried away with all this as there are no unknown soldiers. Under the headstone 'A Soldier of the Great War. Known unto God' are some kind of human remains but they are unknown because no dog tag was found with the remains to identify the death. So I do not not see how the Red Cross records can possibly ID these graves. We know who they are because they did not answer battalion rolls calls and are commemorated on the memorials to the missing like the Menin Gate and the Thiepval Memorial. We also have the variations of the unknowns where some kind of ID was able to be made e.g. 'A officer of the Great War' 'An Australian of the Great War' 'a Royal Warwicks of the Great War' etc etc.