I think you should keep it the way it is. If you make a drawing out of it every time that will attract new members that are never on the forum plus people creating multiple accounts in order to have more chances in the same drawing. In the end it's up to you though, your giveaways your rules.
You're right. But we already have a "rule" in place where generally GWAC doesn't give codes to someone who just simply joined and has only their one post. ( Then again... look at me.
So if that was a little more enforced then that would defeat the possibility of people creating spam accounts. To quality, maybe that person should have a minimum amount of post. Again, probably throwing myself to the sharks.
I think everyone should pick a number and then you decide which one is the winning number.
Or make them play BINGO !
Oh.... Who else but Quagmire!?