Why should an interior designer be licensed?
An interior designer is a person who holds a valid certificate of registration and a valid professional identification card issued by the Professional Regulatory Board of Interior Design (BoID) and the Professional Regulation Commission (PRC) pursuant to Republic Act No. 10350 known as the Philippine Interior Design Act of 2012 (Implementing Rules and Regulations of the Philippine Interior Design Act of 2012).
ABS-CBN covered an incident involving a person claiming to be an interior designer whose modus was running away with his clients' money and not finishing his job.
American designers and decorators are no exception when it comes to their state/local regulations. Famous decorator Kelly Wreastler was arrested and summoned because she was not qualified to practice interior design in the state of Florida.
Source: Florida Board of Architecture and Interior Design (Ed.). (2008). Probable Cause Panel Meeting. https://drive.google.com/file/d/1KDuxXP8XSGqVS7EiJy2BByJ7FDcpyHKl/view?usp=sharing
What if one practices interior design without a license?
You will be punished with a fine of not less than three hundred thousand pesos (Php300,000.00) but not more than one million pesos (Php1,000,000.00) or imprisonment of not less than six (6) months but not more than three (3) years, or both fine and imprisonment, at the discretion of the court (Implementing Rules and Regulations of the Philippine Interior Design Act of 2012).