I have passed all of the Piano Technicians Guild (PTG) Registered Piano Technician (RPT) exams:
I tune pianos completely by ear without the aid of so-called tuning machines. I have nothing against using these machines except that for me, they would not result in greater efficiency. Machines are good as an aid but shouldn't be used solely to determine the tuning, as corrections by ear typically need to be made anyway.
The Piano Technicians Guild is an international organization of participants in the piano trade.
I also hold a BA in Music from SUNY Stonybrook and a BS from SUNY Albany.