Some methods of fingerprinting are probably used to distinct between real users and bots. Bots can use patched headless browsers that are masquaraded as desktop

Some methods of fingerprinting are probably used to distinct between real users and bots. Bots can use patched headless browsers that are masquaraded as desktop browsers (for example as latest Firefox or Chrome running on Windows). Subtle differences in font rendering or missing audio support can be useful to detect underlying libraries and platform. Hashing is used to hide exact matching algorithm from scammers. There is a lot of people trying to earn on clicking ads with bots. Edit: and by the way disabling JS is an effective method against most of the fingerprinting techniques.