Disabling right click causes some other issues as well that need to be thought about, all the other options that you can use with right click would be disabled as well making things more difficult for legit members to use these functions.

And with all the other ways to grab images, I'm not sure that disabling right click would stop even one ripper.  

As we stated before, we did disable it and it was not well received by many many legit members and it didn't stop the image ripping so I don't know...

My 2 cents, personally.. not speaking as an admin just my view on disabling right click.