But as chilli says how can ATCO's second guess the state of the aircraft when the new ones have next to no experence in the air.
Its not a case of 'how can atco's second guess?'. But WHY the ATCO's have to second guess. experience 'in the air' has little to do with an ATCO declaring an emergency or not. How does the ATCO know what experience a pilot has??? it isnt often mentioned as a pre-requisite to a mayday, how many hours the pilot has on type. Something which is not so serious for a senior Flying instructor may be an absolute crisis for a low hours ppl. That isnt for the ATCO to judge.
Secondly which is the better scenario? An ATCO deploying RFFS for a relatively minor situation? Or the ATCO sitting back, thinking 'oh he'll be alright' and finding that the plane digs its nose 100m short of the runway????
As another point:
By second guessing you are removing the PIC from the loop
It is not neccesarily removing the pilot from the loop, If the pilot has failed to declare a situation which: A) may prevent safe and effective flight. B) upon landing may affect the servicability of the runway, then the ATCO has to make a decision to also protect other aircraft in the 'bigger picture'.