I think that identification on departure would only be neccessary for a/c that EMA approach would work, rather than a/c that are sent straight to ACC. In this scenario, TWR should use the intercom to tell the approach radar controller the airborne time in order for the necessary identification to take place within one mile of the end of the runway.
It is highly unlikely that the controller in radar would be listening to the ADC frequency!
Passing airborne and landing times seems to be a procedure that I've only ever heard the "older" controllers use at different units. Please tell me if it was ever in any way useful, as I think it is a totally useless transmission in the modern world.
That's my honest opinion. Over to the rest of you...