If those risk management systems are themselves software, that doesn't really change the overall picture.
It does because the issue is complexity and opaqueness. A simple gatekeeper filter along the lines of
if (trade.size > gazillion) { reject(trade) }
is not an "AI system".
In which case the AI splits the transaction into 2 transactions, each just below a gazillion.
There have been a couple of brief discussions of this in the Open Thread, but it seems likely to generate more so here's a place for it.
The original paper in Nature about AlphaGo.
Google Asia Pacific blog, where results will be posted. DeepMind's YouTube channel, where the games are being live-streamed.
Discussion on Hacker News after AlphaGo's win of the first game.