~snip~
As far as I recall, referral links are
permitted in the signature area. I don't think users should be tagged for that. Perhaps this is something forum staff could clarify?
Categorically no referral links in the body of posts, but that's arguably something better suited to being dealt with via the 'report to moderator' button. Trust doesn't really come into it unless the site they're linking to is a ponzi scheme or something else malicious.
Of course ref links of HYIP site whether they are in a post or inside a sig code sure needs to receive a red tag. Most of the previous tags I have seen coming from sig codes of gambling sites comes with a shilling of the website encouraging them to click their sig code which of course contains their referral link. So I think shilling the gambling website also needs to be considered when it comes to tagging them or not.