You've assumed avoiding prosecution was the aim! I feel it's underwood around the literati that it's trivial to avoid being caught and so anyone who hands over money is doing so for morality or convenience. For most e-books (anything mass-market or academic) the convenience is better for piracy so my suggestion was for someone who didn't want to feel they weren't properly rewarding the author/publisher.

My bad, sorry.

However: We all know that creators don't get the whole money you pay for some works. If I would want to support a creator I would try to find a way to support directly.

In other words I find it a bad idea to buy a book as a way to donate.

Buying a book does much more for an author who isn't already famous than just giving them money does. It raises their visibility, making it more likely that publishers will bite on a second book by them. It also pays the editors, typesetters, etc. - the author isn't the only creative person involved, and every heavy reader can think of examples of authors who have good ideas but desperately need an editor.