How Do Crowdfunding Platforms Protect Their Users From Fraud?

We had to come up sort of with our own classification and kind of have a realistic expectation of what we could classify or not rigt. A very bad type of fraud would be, i create a crop funding page for my best friend but then never deliver the money. We were aiming to get allf the campaigns that were relevant to organ transplants. That was our mission, our goal. And so we candied a study of major organs-related crowdfunding platforms. For example, go funmy has a antee that they will return the money to the donors if the campaign is found to be fraudulent. There must be some mechanisms ready in place. How do the platforms protect their users from