I highly doubt that the system would take trailer brakes into part of its equation. There's just too many variables to effectively tune it for all trailer applications and maintenance practices out there...
I bet if it's like my traction control on my Expedition, 9 times out of 10, it is an annoyance. But when it saves your you know what, you swear by it.
I hated my traction control until I found a bit of black ice, started to go sideways, and the truck had itself back straight before I was able to react.
I wish I had a system like that for towing as most of you do....... I guess it's just another check in the column for buying a new tv.