We watched the documentary "Beavers" and it was great. The accompanying "How this was made" part though was sort of disappointing. The beavers were totally conditioned to the film crew so they weren't exactly natural. On the other hand, they wouldn't have been able to get many of the shots they did if the beavers weren't used to them being around. So I guess in the end there's a trade off between filming wildlife completely unaware vs. getting more intimate footage that you couldn't otherwise.
Unnaturally staged or contrived footage is, of course, another story.
I don’t care what they have to do to get their shots, but TELL US. Full disclosure. Planet Earth series didn’t fake shots and they also told us how they did it. Stayed out in the freezing cold for weeks or months to get a shot. They could have saved a lot of time & money by going to a zoo and faking it. But then it wouldn’t have been REAL.