We use a weighted lottery system to make the process as fair as possible. At the beginning of each calendar year, every member's Lottery weight is set to zero. If a member requests a registration but is not selected, their weight is incremented by one. When that member requests another event, they have a higher priority in the Lottery as it picks members with higher weight first. So, if a member was not promoted for one event they have a better chance of being promoted for the next event for which they register. Once a member is promoted to an event, their weight is reset to zero.
With this system, on average, members are promoted for approximately half the events they request. However, there are other factors that affect how many times you are selected for a Lottery event, including popularity of the event, size of the venue, and the number of events you register for. If an event does not have enough guests register to meet the venue size, all who sign up are able to attend. This is the reason some members attend more events than others.