Author here. Honestly, I don't have a good answer. I spread my capital across enough exchanges so that if one runs away with it gets hacked it doesn't ruin me. It's just a risk I'm taking.

I'm also not trading much capital. Because the system is more on the HFT side, the actively traded capital isn't that high, and I don't care about losing it. Any profit I try to get out of the exchanges regularly. I wouldn't feel comfortable leaving large sums on those exchanges.