LOL. They wouldn't really be happy if they knew, but they will think you're being tracked. I'm sure there's at least one (probably several) ad blockers available for FF. I use adgaurd and am very happy with it. Their computer wide version is not free, but the browser specific ones are free. I use Opera most, so I have it for that, but they have one for FF, all of the browser specific versions are available here:

https://adguard.com/en/adguard-adblo.../overview.html

This will not stop you from being tracked, but it will block the ads sites try to show you on the basis of their tracking of you. I like this approach because it doesn't stop cookies which often are required for websites to work properly. And as I say, even if you stop cookies, you still see ads, they're just more random - not targeted at you.