There should be a certification organization which reality shows would proudly display membership of, if they wish the public to believe they are actually truthful.
I'm not talking absolute truth in film, but there are some really easy steps that the pubic deserves and expects:
Right now, there's no way for honest institutions to distinguish themselves from liars. Every documentary and reality show claims it's true, yet a lot of them are fake. Genuinely true ones should have the ability to make their words and claims more credible, by publicly stating the above.
Most shows wouldn't adopt this - but it would be great if some did. It'd make those shows more credible, and it'd reduce the credibility of ones which didn't.