You can use a combination of the disguises and stealth to get through the prison almost entirely without being seen. It doesn't really matter if you're seen, though, because you can then just lie/persuade to get past the few tough spots.
The game mechanisms are cool, but everything needed more tuning to find the right balance in difficulty. It's definitely too easy in normal mode.
I agree with stiven that the factions showing up to help you is unnecessary, unexpected, and disruptive the way it's currently handled.