Oh right, Guard Houses. I had conquered one before, but never put it to use. I guess simply not doing anything is putting it to good use, for my thieves. I'll look into taking them over. And it still strikes me as weird that the town doesn't really mind you taking over their police stations through murder, then privatizing them. Whatever...
That brings up a question in my mind: If you have a job as the guard captain, (or something in that branch), or maybe even as a judge, can you use those jobs to negate a botched criminal activity? "The court finds in favor of... myself. We're adjourned."
Thanks for the tips on the Robbers. I will keep those in mind. I am glad that a thieve's guild Master is decently efficient. I suppose I will keep some spare change around on the odd chance they botch a job... unless I take over the guard houses.
I've gone and spewed forth lots of text so better split it up to avoid TL;DR disease:
Firstly, as judge you are immune from prosecution - so you can do what you want and get away with it! However for some reason your underlings can still get fined (and you can't avoid that) - it's just that no one can take you to court for it.
However, be aware that crimes recorded against you still exist!
That and your crimes are passed down to your heirs for some reason. So what I'm saying is, make sure you clear your criminal record once you're no longer Judge (or one of the other offices that have immunity). I once had a situation where my character died (as a Sovereign), passed everything to my son - then he gets called to court for all of these crimes his dad committed!
Something else that's fun to do - blackmail the dude(s) in charge of laws for kidnapping, thieving, etc. and get them to change the laws to make it legal! Or get into the office yourself and do it. For some reason as soon as a new candidate gets in, they always revert those things back to illegal. No sense of adventure some people... ;)
Unfortunately the guard captain office (or captain of the guard or whatever it's called) doesn't appear to actually provide you any actual benefits in the game. It seems that the "guards" that you're supposed to be in charge of are actually Rent-A-Cops, and you have no influence on them whatsoever. Which could explain why no one complains when they're all taken over.
More thoughts on Guards:
What I tend to do is use the remaining guards to launch a suicide attack on another guard house (or thief/robber joint) to hopefully kill a few of the more experienced dudes, then follow up with a "proper" attack from my thieves/robbers. The killed dudes seem to get replaced really fast, but at least they'll be crappier so you'll take less casualties for the guys you care about.
More thoughts on thieves:
I am fairly disappointed that those options for your hideout to keep it "hidden" don't actually seem to do anything. It would have been pretty cool if you had to actually find
thieves guild's or robber baron's castles before attacking them.
As for thieves getting caught - it's pretty rare since they don't burgle things that often. On the plus side they sometimes burgle things that you can't actually burgle yourself (e.g. Country Estates - you can't do it since they're technically a level 4 building and the Thieves Guild only allows up to level 3). On failure, the most you ever get fined is a few hundred bucks, so unless you're racking up mountains of debt you should be fine.
IMO if you don't want to micromanage and you're bothered by the drop in income, you can always just focus on kidnappings. That's the biggest source of cash for a thief anyway, yet the AI never does it, and it's only a few clicks to do. Plus it's handy when you have an upcoming election and you need to ensure that parties that may not be intending to vote the "correct" way are temporarily removed for their own safety... ;)
More thoughts on Robbers:
Also, I reckon you'll quickly realise what I did - that playing the Robber is a pain in the ass. Maybe because I expected that sending a bunch of heavily-armed thugs lurking in the bushes, ambushing a cart and then defeating the enemy would actually be more profitable than thieving. Unfortunately, it's a lot more work for a lot less payoff, unless you get lucky with a cart full of something expensive. It seems like the AI likes to transport small numbers of cheap crap most of the time - but let me know if you have better luck.
One final thing I forgot to add last time: attacking "businesses in the surrounding area". The only one ever worth it is the mine (although it can be funny to think armed robbers stealing planks of wood from the forest, or chunks of rock from the quarry), but if you time it right you can get cart-loads of gold and/or jewels. Just ditch the "raw" gold/jewels as unfortunately you can't sell them...