Navigating by the Intel's OpenCL forums I found this:

It's a thread talking about encrypting OpenCL kernel's source.

I agree that currently we have a problem: it's very easy to get your source code so it will be very easy for a hacker to get it. Think that many companies are placing comments and IP inside that source code so I think will be good to design a way to make hacker's life a bit harder in this aspect ( there is no perfect solution and all can be hacked but.... )