What they need to remember is that with that tuition check comes an opinion. Kind of like a gift with purchase.
I am all for following your dreams and finding your passion. But you have to have a little "skin in the game". Your parents don't support your desire to major in vocal music or fashion design? Here's an idea...get a job and pursue your dreams all by yourself. Do whatever it takes to make it happen. I think somewhere along the way we confused the ability to find something you are passionate about and you will be able to make a living doing it with it being easy.
Following your dreams is often anything but easy. You make sacrifices and take risks that aren't always comfortable. You don't always have the support of everyone around you. You keep moving forward because you believe in what you are doing, not because it is easy and everyone is your cheerleader.
So my advice is follow your dreams, but remember it won't always be easy!