Most companies providing tracking scripts require that you inform your visitors about the way you use their data. This is standard practice for Facebook or Google tags.
Show a non-intrusive message that doesn’t bother your visitors. You don’t want to block your content or disrupt your website’s usability.
Inform your California visitors about tracking. Use a small popup, that is easy to see, but is not annoying.
Show each visitor the correct message, depending on their location.