I recommended to one community manager that he give each community member 10 invites they can use throughout the year.
He spent $853 on a programmer to write this code into a website.
Why not just tell members “you each have 10 invites throughout the year, use them wisely”. If they ‘use’ more thank 10 invites, great. If they use less, then you didn’t need the code anyway.
Two lessons here. First, most of your community members want to play by the rules. Two, before every single technology expenditure ask: Is there a social alternative?