I have to disagree this time, Richard
That law is one of the very few in this country that actually makes sense. While the idea of influencing people by 1-frame "subliminal" messages specifically has been discredited, the principle behind the law is valid, given the mind-controlling sociopathic mentality of the advertising industry. As you point out, the key point is outlawing "attempts to convey information to the viewer by transmitting messages below or near the threshold of normal awareness".
In other words, the advertising industry is not allowed to use ANY form of consciousness-bypassing techniques to try to make the viewer want something they normally might not want. Considering that the raison d'etre of the advertising industry is to get inside our heads and psychologically manipulate us into buying useless tat, this law is based on sound principles.