That seems like it might be difficult to pull off considering Google is most definitely not invested in Touhou nor do they likely care about it whatsoever if anyone even knew what it was; plus it would require modifying the whole reporting and takedown and error system. The thought for Youtube and copyrights in general would be a good idea, however, and many self-publishing game and music artists make use of similar tactics already to a very successful degree.
Something that could work quite well if done properly would be a video purposely labeled as "How to Download Touhou", where the video's contents would be explaining the series, explaining derivative works, how Touhou is indeed not free and so on, while also providing links to the demos and legitimate outlets to buy the games. This video would then be bombed for viewcount and favorites to manipulate common video suggestions. Unfortunately though I have to admit that the outlets that do sell the games are sold out quite often and don't carry much in terms of stock, and without a steady supply it's quite difficult to tell people to purchase a game that they aren't really invested in yet when the place you tell them to go is out of stock. Now, it's something ZUN doesn't seem to want to do, but putting up a donation site would almost definitely motivate people to purchase the game, or rather download the game through means we already have and then simply donate if they feel as if it's worth it. That would be something that could easily, easily work its way into the entirety of the western fandom; something that could be posted everywhere on the net, even on places that are as pro-pirating as you can get; something that you can even plop in the game itself in english patches and whatnot. It's an idea that I really think could work, but it doesn't really seem to be something that ZUN intends on considering, judging by things he's said in the past. I wonder if it's worth calling him up again.
