Professional associations such as the Association of Legal Administrators (ALA), although well recognized as valuable tools of American business, are subject to severe scrutiny by both federal and state governments.
The single most significant law affecting professional associations is the Sherman Antitrust Act, which makes unlawful "every contract, combination in the form of trust or otherwise, or conspiracy, in restraint of trade or commerce…"
A professional association by the very nature of the fact that it is made up of competitors is a combination, thus satisfying one of the elements in proving an antitrust violation ... excerpt from ALA Antitrust Guide for Members of the Association of Legal Administrators.
Please review the full Antitrust Guide on the ALA website. You must log in as an ALA member.