There is none, however there's a problem with not communicating that in plain English, i.e. "we sell the spots on our preferred search engine list to generate r

There is none, however there's a problem with not communicating that in plain English, i.e. "we sell the spots on our preferred search engine list to generate revenue, as of now a few companies have not agreed to those terms and are being removed". For good reasons the general convention is to render sponsorships and ads visible.