If this feature is going to be well-known and too easy to discover - it is already doomed. As soon as too many ordinary users start using it, advertisers will invest in workarounds. Ad blocking only worked well as long as the majority of people didn't care to use it. Ad blocking and privacy-enhancing features should be off by default, requiring you to dive deep into config dialogs to turn on so only those who actually worry about being tracked would use them - this way this can have a chance to actually work.