Basically the impression I get is if you get caught doing ANYTHING wrong everybody just puts you as kill on sight.
You are getting the wrong impression.
Generally the ATTITUDE of people towards the character getting caught doing something wrong is what determines the reaction. If they've got a high attitude towards that person, you'll usually lose 5 or 10 points of attitude when you get caught and will need to get caught repeatedly to bring yourself down to the level where there are severe consequences.
If you are going to risk getting caught in the first place, it is advisable to do it with somebody people like.
As an extreme example, have your groups's face and crimelord be an altruistic politician with a few points invested charisma.
Alternatively, just bribe the people you are concerned about observing you, remembering that attitude is capped at 100.
I don't disagree with you that having the possibility of paying a fine or being thrown into jail for a long time would be interesting alternatives to have regardless of people's attitude towards you, but I don't see them as hugely compelling as that would further reduce the value of the attitude system in favour of letting people get easy outs not only when they commit crimes by mistake, but also by intent.