States test the competency of professionals before issuing a certificate, to protect the public. Professionals are independent in that they may operate their own businesses. Independence eliminates many conflicts of interest because the client does not employ professionals. Rather professionals contract with clients to provide services for a fee. Since professionals have many clients, they can afford to turn down improper offers from any ONE client.
Professions enforce a code of ethics.
Egregious violations of the code of ethics result in a loss of license, though there are lesser penalties also. Finally professions maintain a body of knowledge. The accounting profession demands a commitment to livelong learning. Standards and tax laws are constantly changing, so accountants must continuously study to stay abreast of the profession. CPAs must attend at least 40 clock hours of continuing education every year to maintain their CPA license.