Even though I'm willing to bet most people who end up in the system are doing things to put them in that situation (though maybe thinking otherwise would be too scary a prospect and I'm reassuring myself here), I wouldn't be so dogmatic in thinking that as long as you do x and y, it will always equal z. Like in the link I posted, the first guy got taken in simply because the month long friend of the victim was asked to throw out a name she thinks might give them some headway in the case and she said "Oh I would talk to the next door neighbor

" and that was all she wrote. You never know, it could be you one day.
There is a argument to be made that the system is not about justice as it is about efficiency to get a case in and out of court. Its done under the pretense that the constitution guarantees a fair (

) and speedy trial. There is a reason why plea bargains or trial by judges are pushed because they're much more efficient and speedy and there have been studies that claiming your right to a trial by jury actually tends to be more punitive and is used as a way to coerce defendants from using that option. This system leads to things like questionable interrogations and tactics used to speed up the process.
In regards to the first 48, there have been a few episodes where the way the cops went about things made me pause.