I have expanded this discussion to include licensing, with this being the obvious option that doesn't get discussed. Sometimes instead of trying to use locks (part 1), levies or lawsuits to enforce a specific business model, that using an alternative licensing mechanism would work better.
I covered the topic of levies before on this blog with an article titled "Analyzing when copyright levies are a good idea, and when they are a very bad idea.". In this article I spoke about what are called "compulsory licenses" where a copyright holder can no longer require permission for an activity, but where a royalty fee is imposed. I gave a suggested test for the extreme situation that warrants such an exception to copyright, and tried to apply this test across a few different proposals (The Songwriters Association of Canada proposal that I support, and the Creators’ Copyright Coalition proposal which I strongly reject).