A good idea, but I'm afraid that whenever any amount of money is involved, confidence, reliability, good behavior and trustworthiness are the first principles that get thrown overboard.
That being said, there are a number of people on this forum who are very trustworthy and wouldn't even think of pulling one on you. One of the reasons I like this little community.
And as we say over here: It takes years to build up a reputation and just minutes to destroy it