Money is the best motivator to encourage people to act in a certain manner, so this is a great idea in my opinion. There will always be people wanting to exploit anything, so the people that want to add substance and value to something will just have to navigate these "potholes". Not much can be done to stop the bot comments and spammers. Just gotta go around 'em, flag 'em when we see 'em and hope for the best :)