We implemented the same policy for the last two reunions. We used color-code tickets - different color for each event - and had someone at the door taking up tickets. This one incident that I mentioned, that family still received their tickets because they told me at the reunion that the co-treasurer had deposited their money. I took their word for it and gave them their tickets. However, they conveniently failed to mention that they only paid for 2 people, and they had 10 in their group.