If someone visits your website and then leaves without engaging with it, maybe the website design sucks, or maybe they didn't want what your site was offering. There are lots of valid, non-creepy ways to figure things out. Stalking those visitor isn't going to improve anything. There are so many good things you can do with AI. But ideas like this destroy trust in the technology and industry. Creepy. (And yes this will run afoul of laws in various jurisdictions.)