I think ATCOS (and pilots) are wrong to announce on the RT that they "are going to file". It's like shouting, "I'm telling my Mum!" If the reporter believes that safety was at risk, an MOR is filed and that's it.
The reason an ATCO is supposed to tell the pilot he is filing is so that any relevant information can be placed in the flight log or voyage report by the pilot.
Then when it's tea, no biscuits, and hats off, in front of the Chief Pilot 5 or 6 weeks after the incident at least there's some chance of remembering what the hell he is going on about.
It works the same way in reverse too. If a pilot is filing for something involving ATC, then unless they are told at the time (or by a phone call to the Supervisor on landing), there is a very real chance that any radio or radar recorded data may have been overwritten (mandatory 30 days retention for radio tapes, 15 I think for radar, and 6 months for strips). As it may take a bit of time to filter through the company reporting system, then SRG, then the ATS providers management chains, before getting back to the ATCO involved, there is a strong chance they won't remember anything about it either.