Most states have laws against this. State legislators often are opposed to it but the attorney generals of the states just look the other way.
Much is written about it but a quick search shows this.
Medical practices of all types are subjected to various regulations from business formation to HIPAA compliance, and everything in between. Depending on the circumstances, these rulings may come at a state or federal level. It is important that practices are informed of these regulations from...
fentonlawgroup.com
Also some good info here.
For anyone who is so indoctrinated into the current system please do consider that lawyers and accountants havent been bastardized the same way medicine and EM has. Law firms are owned by lawyers, arent publicly traded etc. Those guys dont want to get abused.