As commented above, as long as - it's a one-off thing - there's explicit disclosure - the answer is a good quality one and stands on it's own then I don't think there's a need to remove the referral link. If the referral link is the only thing that's being blasted across - then you know [where & how to make use of the spam flag][1]. [1]: https://meta.stackexchange.com/a/58035/133693