My examples here may not be of hidden music agendas, but it is the best way I can relate to this discussion.
I have attented nutrition conferences only to realize later that the material presented was researched and presented by animal rights activists.
I have attended osteoporosis forums funded by the Milk Marketing Board.
I have been a speaker on The Benefits of Soybeans funded by a large soymilk company. I will never do that again
Canadian Dietetic Association has the following corporate partnerships: Milk Marketing Board, Sugar Industry, Meat Marketing Board, Pork Marketing Board, Egg Marketing Board.
Scientific research papers that show the benefits of one glass of red wine per day to reduce heart disease was funding by the red wine producers.
'Eggs aren't so bad for cholesterol after all' was funded by the Egg Marketing Board.
How about going out with a friend for lunch and at the end of a lovely time together being pitched to sell BlueGreen Algae, Amway or some other pyramid marketing product.

When I am exposed to these kind of situations, I try my best to discern where the information is coming from. Take from it what is of value, if any, and drop the rest.
But it does leave me feeling saddened with a bit of a heartache.

Little Neo