Why does one announce "Thrust Set"? I have watched many aircraft takeoffs now where the flight deck announce 'Thrust Set', just after the engines are set to full. 

Forgive the dumb question, but why does one announce that the thrust is set, perhaps more importantly, why is it necessary in the takeoff procedure? 

I did attempt some research before posting, but the closest article I got did not make much sense to me I am afraid. 




  For the GE CF6 engines, N1  should be stable at 70% before the TO/GA switch is pushed to set the armed thrust limit. If TO/GA is not pushed by 50 knots, thrust must be set manually and when VNAV goes active at 400', the A/T will automatically go active in THR REF, so you don't need to select anything if the A/T is armed.
There was at least one incident where a Boeing 737 attempted to takeoff with the throttle levers not set to takeoff power.

The procedure is designed to ensure


the thrust lever is where it is supposed to be
the engine indications show the correct amount of power is produced


In some airlines, the procedure calls for both pilots to put their hands on the levers and advance them together. Either way, the purpose is to have both the pilot flying and pilot monitoring to ensure takeoff power is properly applied.