I had a bunch of sites on a shared host a while back. I got an email from the hosting company saying they'd had a legal notification from a site I was linking to that demanded I removed links to their website or they'd take legal action against the host (and me by extension?!).

Despite me pointing out the ridiculousness of the situation, as well as the SEO benefit to the original site no one would listen and it ended as "remove the links in the next 48 hours or we take down your sites until you do."

Wasn't worth the fight, so I removed them. Still can't get over the waste of resources and the ridiculousness of the whole thing.