There are several data-broker-esque "services" that actually do this already with FB, Google, etc assets (favicon.ico and similar, loggedIn urls, ...) to check whether you have visited those pages, or whether you are logged in to those services by trying to request a URL that might return a large image if logged in, or fail rapidly if logged out. -- This has been a thing for a long time:
https://news.ycombinator.com/item?id=15499917If you don't use any of those sites, you're considered higher risk/fraudulent user/bot.
Here's an example of a very short and easy way to see if someone is probably gay: https://pastebin.com/raw/CFaTet0K
On chrome, I consistently get 1-5 back after it's been cached, and 100+ on a clean visit. On Firefox with resistFingerprinting, I get 0 always.