Who could possibly not be a vested interest? It's hard to think of more than a few cases where I've personally wanted to learn about something and didn't, at some level, hope for one answer or outcome over another. "Ban vested interests" is an impractical policy. stevenhuang's suggestion to be aware of them is much more practical and has the benefit that "vested interests" who truly do wish to fund an objective study aren't stopped from doing so.
GP just means that effectively that's what will happen. just like wow churches push money through think tanks and orgs that donate to political campaigns. The money will never go away it will just get darker and darker and darker.
No, we should ban vested interests from funding research studies and reduce the SnR.