Everywhere I see anything written about exercising the pecs with the cable standing fly, the form is the same: Bend hips, elbows and knees slightly and bring the handles down in front of the torso. But a trainer at my gym teaches a different technique for isolating the chest: stand straight, chest out, arms extended from shoulders parallel to the floor and then bring the handles down. I have not seen her method listed anywhere, and I was wondering what the pros and cons of this method are when compared to the traditional method.
That sounds sort of like a description of the move pictured above, maybe without so much forward bend at the waist. Pretty standard form for a standing cable fly, also known as a cable crossover. Some coaches will say to bring the hands to meet at waist-level, chest-level, or face-level, sometimes for different emphasis.
If that's the way I'm picturing it, you start looking like a T, standing upright with your arms straight out to the walls, and then you bring your hands straight down to your sides, so they end up by your hip pockets. If that's correct, it would be less of a pec move and more of a (crappy) lat movement. Almost like a stiff-arm pulldown/pullover gone all screwy.