Without direct testimony, it's not reliable. You need someone, under oath, explaining what they said and why. You can't take a conversation with out the participant present at face value. I can text anything to anyone I want, it doesn't mean I believe it. I could be joking. Autocorrect may have changed my words. Someone else may have grabbed my phone. Only until I'm testifying under threat of perjury can it be considered evidence. Other wise "evidence" can be easily manufactured. You don't think Johnny's lawyers submitted evidence that wasn't admissable?