Most of it is context and how a reasonable person would interpret it. Fake ads are commonplace on SNL (they aren't always for real brands), they use comedians k

Most of it is context and how a reasonable person would interpret it. Fake ads are commonplace on SNL (they aren't always for real brands), they use comedians known for being on SNL, and are often very silly. No reasonable person watching SNL would see the Jim Carrey Lincoln MKC commercials and believe that Allstate and Lincoln were really airing a joint commercial in which Jim Carrey runs over Keenan Thompson in his Lincoln. But if they started airing those outside of SNL during regular commercial breaks things would probably be different. It's the same thing with that Onion article. Anyone familiar with The Onion knows it's parody, and anyone not familiar will find notice pretty quickly. The article also doesn't make any false assertions or libelous claims against Clinton. It's just using her image to parody the idea of her pandering to an audience. Also, less of a purely legal reason but, you only get in trouble if the other person doesn't like it. Brands are usually very happy to have their stuff parodied in a lighthearted way. Weird Al always asks permission before parodying a song (even though legally he does not need to), and almost never gets a no. More often than not, artists are incredibly excited to be parodied by Weird Al. To use the SNL Lincoln example again, SNL's fake advertisements had many times more views online than Lincoln's advertisements. All for free (for Lincoln)! They're getting people to watch for a minute or two a video all about the new Lincoln car, and they're not making fun of the vehicle or the company, just the strange acting in their real commercials. Jim Carrey never says "the acceleration in this thing sucks" or "the windows are too tinted, so I can't pay attention to the road", he just goes off on weird existential musings while twiddling his fingers.