There is nothing that I am aware of that "legally prevents" us from giving advice Euro - I have no idea what you mean. Now - we may choose (as individuals) to not give advice and people should be aware that we are just a bunch of people giving nothing more than opinions (some educated opinions, some not). But "legally prevented"? No.
Oh, there are many prohibitions in both state and federal law on this point. As just one example, an excerpt from Georgia State law:
"15-19-51 Unauthorized practice of law prohibited.
(a) It shall be unlawful for any person other than a duly licensed attorney at law:
(1) To practice or appear as an attorney at law for any person other than himself in any court of this state or before any judicial body;
(2) To make it a business to practice as an attorney at law for any person other than himself in any of such courts;
(3) To hold himself out to the public or otherwise to any person as being entitled to practice law;
(4)
To render or furnish legal services or advice;
(5) To furnish attorneys or counsel;
(6)
To render legal services of any kind in actions or proceedings of any nature;
(7) To assume or use or advertise the title of “lawyer,” “attorney,” “attorney at law,” or equivalent terms in any language in such manner as to convey the impression that he is entitled to practice law or is entitled to furnish legal advice, services, or counsel; or
(8) To advertise that either alone or together with, by, or through any person, whether a duly and regularly admitted attorney at law or not, he has, owns, conducts, or maintains an office for the practice of law or for furnishing legal advice, services, or counsel." (highlighting included).
In my practice as Business Consultant it is mandatory to make 100% clear that I am not providing legal advice to my clients in any form or shape.