What if someone links to my website but I don't want them to?

Nope. Any reasonable person probably would, but there’s no obligation. Just ask nicely :)

(Anyway… Why don’t you want your website linked to?)

Thanks Vincentt, just a hypothetical question for some T&C I’m putting together

That’s the Internet, baby!

There was a test case on this a few years ago. A content-holder wanted to control who linked them by asserting their copyrights. I don’t believe they were able to prevent linking altogether, but there was some case law asserted that made a distinction between “linking” and “deep linking” (ie. linking directly to a page other than the home page on another site). I don’t recall how it worked out, but Groklaw had some info on it, and a Google for “deep linking” might be useful.

That’s just the way it works unfortunately I normally will shoot them an email asking if its okay to link to them. Most people have an image and a link to me with this address

no such thing,