I guess what I'm trying to ask is, is there any reason not to just completely prohibit referral code? They are mostly spam and not really beneficial to the forum. And then it will be a clear line of execution.
Spammers and promoters of some types of advertising should be banned altogether.

What is considered referral code spam? One of those full on advertising posts with referral codes all over it like were posted when tradehill opened? What if it's a little more subtle? What about low content posts with the code in the signature?

I guess what I'm trying to ask is, is there any reason to not just fully ban referral codes? They're mostly just spam and don't really benefit the forum any. And then it'd be a clear enforceable line.

Just a thought.