Mika Epstein has a post on why you shouldn’t use copy protection to try to protect your content. This of course applies to websites. I think you should go read the post, but the short version is this: It doesn’t work.
If you look at the post, you’ll see some very easy ways to get around said protection: Developer tools. These are the tools developers will need to bring up if we’re going to help you fix problems with your site, especially when we’re answering questions in the WordPress support forums. By disabling right-clicking, (which is what copy protection relies on), it’s harder for us to open those tools. But it’s not impossible.
One of the other methods used in copy protection is disabling copy/paste capabilities. This breaks things for adaptive technology users in all kinds of ways, basically resulting in “We can’t read your content.” If we can’t read your content, we’re not going to visit your site. And we’re going to tell our friends about it. Who will also avoid your site, tell their friends, you get the picture.
Stealing content is not cool. We all pretty much agree on that, content thieves obviously excluded. But given that the standard methods of copy protection don’t work in the first place, people who create websites have a really good reason not to use it.