Ooooh, in a request I got today the person actually used "cease and desist" with regards to linking to their site.
I replied that we promise NEVER to link to their site ever again from any properties we own. I can't wait to attach that in the future if/when they (or an agent of theirs) comes asking for a link. I'll tell them I'll need at least $100 to go back on my promise. :)