That itself is a problem, while we have public defense lawyers, we don't have public preventive lawyers (who I can call and ask if what I'm about to do is altogether legal and what can I do to avoid run-ins with the law).
1. They are tasked to give well researched legal advice in all fields.
2. Their advice should be minimally restrictive.
3. If a person faithfully follows the advice of the office the office assumes criminal and civil liability.
Individuals are not capable of evaluating the law without the aid of legal professionals. Worse, individuals don't have the ability to evaluate the quality of lawyers. This system would allow individuals to be secure that they're not heading into legal gray areas or situations where the legality is truly unknown until there's a trial.
I like this kind of system because it's in the best interest of such an office to give the most accurate advice possible.
> 3. If a person faithfully follows the advice of the office the office assumes criminal and civil liability.
The problem is these two are in conflict. If the office gets in trouble for approving something they shouldn't then they'll have the incentive to be overly restrictive in what they approve.
A better solution is to make this office a subdivision of the justice department and then if they say you're allowed to do it then you can't be prosecuted for it. And if they say you aren't allowed to do it then you can hire your own lawyer to appeal the decision to a court, and they get penalties for being wrong.
If you don't want people looking for loopholes then don't put so many in the law. When you pass thousands of pages of tax code and then companies spend a lot of time trying to save themselves billions of dollars, what did you expect to happen? That's what happens already.