Most rev-share programs pass back refunds and chargebacks, most pay-per-signup do not.
We, personally, trust our anti-fraud enough that we do not pass chargebacks back. This is not an invitation to start fucking with us (to you scammers out there) because we will cancel an account for fraud.
But, like CJ says, if you have confidence in what you do, it shouldnt be a problem. And there's nothing I hate more than seeing a negative in my stats... it just shouldnt go that way
(we also dont charge for processing
)