That's how I think we should combat things like PRISM. If there was a mass protest every week, by millions of individuals, all searching/texting/emailing "kill president" "home made bomb" "chemical explosion", that data would become really really heavy. They might have to cut back on drag-netting everything and focus on specific targets.
while they claim that such data is used for "fighting terrorism", i really doubt that's actually the case - its more data retention, and availability when required for intelligence operations against targets that benefit the administration. So such polluting wouldn't really help imho.
Not only that, the real problem isn't being noticed today. The real problem is how much shit they have on you when they do eventually notice you. After they pull the string on a US Attorney's back and point her in your direction, she will use every scrap of data available to make as ridiculously overblown case a case against you as she can. Which problem these sorts of protests seem to make worse.