I once served as the liaison for a couple of mayors to a committee promoting the employment of people with disabilities. The committee decided to sponsor a workshop with a group of distinguished speakers. We scheduled a lawyer to discuss the anti-discrimination laws, an architect to describe how to make workplaces accessible, and a rehabilitation engineer to reveal creative ways to accommodate disabled workers.
And in order to draw a crowd, we didn't charge a dime.
The result? A very small turn-out.
Two months later, we held the same workshop with the same speakers only that time there was an attendance fee. We packed the room.
Now it is possible that the second notice finally nudged people into attending, but I don't think that was the deciding factor. It was the price. When people saw the "Free to the public" label, many of them thought, "It must not be that good." When we tacked on an admission fee, they began to take us seriously.
As Oliver Wendell Holmes once said about the law, it's based on experience more than on logic. There are times when one of our worst enemies is an excessive application of logic. We had our logic, but the audience had its own.