Sometimes they are better off hosting an event to find bugs on their site than hiring some ethical hackers because it might be expensive to hire them. It would be better if they had a security team that could also look for leaks in security holes to immediately find out and fix them before something bad happens to them. The trust factor will be important to manage, especially when it involves big money from its members. If they can keep all the funds on their site from hackers, their reputation and trust will increase.