It's a pain I admit, but such is the burden of maintaining your privacy online. Whenever I set up a computer for friends or family I always do this (as well as blocking flash and javascript as standard) and explain what it entails, because without that they cannot know what they are giving away.
If you are really serious about protecting your privacy online, I imagine you already have your browser configured to deny all cookies except those which you explicitly accept. The tools to solve this problem already exist - either built in to the browser, or easily available as extensions.
I'm genuinely curious about this - what do you think gets done with a browser cookie that actually causes real harm to the user? Perhaps that should be regulated instead of the mechanism for it.
This is just supposed to be like the signs you are required to have if you use cctv, letting people avoid it if they wish to.