Ok I find using the term "consensus" a bit confusing in this context, since that could also be just one or two guys :) What you're really saying is that anyone should be free to run whatever filters they want, which I not only agree with but also matches factual reality right now. (People decide what node software to run.) I believe it would take some ~95% of nodes to filter certain transactions before it meaningfully stifles their ability to make it to miners over the p2p network. Is that what you have in mind when you say you'd ideally want users to prevent what ends up in blocks? (To be clear my question is about the method-- not about the exact number as long as you agree it's a reasonable approximation; it could also be 90% or 99% as far as I'm concerned.)