of course it does not belong to gambling board, people thought its a gambling post simply because op mention lottery, perhaps it doesn't have anything related to gambling. the op would have just make the post without involving lottery because this is just a contribution that involve coin flip to know who to take first.
It is not really lottery though because lottery does not give you a guarantee that you will win but this system seems like you know you will be given a chance to get all the money, you are just not sure when. It is a gamble in a sense that we are talking about work salaries because what happens if there is an emergency but it is not your turn yet?