Yep, while we have no reason to not believe the evidence provided, I completely agree with you that the evidence provided should ideally be able to prove that the material was indeed from the series in question and not fabricated. This is why we figured video would be the best form of evidence, even though it is undeniably a bit more annoying to provide (upload etc) than photo (screenshot) evidence.
By providing unquestionable proof, the teams and LA can focus on tackling the problem together, rather than worrying about whether the claims are legitimate or not.
On another note, something that was not covered in this article is that we want as much proof as possible provided to League Administration about the server issues, so that we can help EA resolve the issues.
I have created a form for this purpose: https://forms.gle/iVbP4tak6aDysqAR7