I don't have physical proof to offer but I can attest to the system in place at a "Full Gospel" church I was once a regular member of. I haven't returned there in quite a few years now and it may have changed since then. But at that time you were required to fill out a very detailed admission form to be a recognized member. This form asked for all of your family financial data and based on this, you would receive a statement every month for what the church felt you owed and you were expected to pay it. Additionally, at every Sunday service, the first 15-30 minutes of the sermon centered on your tithing requirements. I was a little put off by this tact.