I have a solution for the lottery round winner. User asked you many times for clear description of lottery winner.
Give the winner a template at their account and send them a message(email) of their lottery winning.
Example:
"You have won the 1st prize of lottery. To get the lottery winning balance post there(one of your thread link) with your user id and tell that the prize you have won."
I want to say that don't credited the lottery winning balance instantly at user account. Tell the winner to post there with their user id. And when they will post here then credit their lottery winning balance at their account. By this other user can learn about the real winner and they can also check the winner id from here and from the site at lottery round history. By this method you can show us that your lottery system and winner aren't fake. By this we can really found the 10 lottery winner every weak. The user id will be the proof of lottery winner.
This will be a great way for prove your lottery system.
Suppose they know about this forum and they didn't have a membership because they prefer silent reading, there is a big chance they choose to keep being a silent reader because they reluctant to sign up. Thus, under an assumption that the previous and future winners are within the category of those who reluctant, having to post here to receive their prize will habe a chance of backfire where they stopped claiming and playing lottery (buying tickets) because they felt it became troublesome and too complicated.