Ask HN: Has anyone hooked a voice stress analyzer to a call center line?

I called into the phone line of a major shipper to get some answers about a failed shipment. Their main line is all automated with the typical "Tell Me The Problem" prompt and some voice recognition back-end. One my previous calls it took a few times to work my way to the information I needed and talk to a representative. I was a little heated the final time I talked to them after being told news of my package. My voice was not calm and after the second question / answer sequence (it generally took about 5 sequences to get anywhere), I heard "transferring to crisis manager" or some equivalent wording and talked to a human agent.

I am wondering if this is some voice stress detection at work, and if anyone on HN has worked on such a system? Also, what stress does this put on the humans who talk to the customers after the computer has already ticked them off? I'm pretty sure most people don't immediately go back to calm as soon as the human takes the phone, but I might be wrong.