My understanding is that the technology is extremely accurate, in that it's possible to cut and paste genes extremely precisely. But as you point out, it's a potentially dangerous tools, as we don't have the knowledge to see all the consequences using this tool may have. So we can cut and paste genes, but end up with a quite different result than expected in the long term.

So we'll need to use this tool with great care, or perhaps not use it at all. Thanks for the links, I'll take a look at them.