Nope. Plausible deniability is a thing. It's not uncommon corporations and lobbying firm to pay contractors large sums of money for 'image management' and intentional ask no questions about how it gets done.
Everyone knows what's happening, but as long as no one explicitly asks (in a documented form), the benefactors can feign innocence.
> I find it hard to believe these investigators truly think Broadband for America had no idea.
The individual investigators likely know full well that Broadband for America knew what was happening, at least in broad terms. But knowing something and being able to prove it in a legally actionable way are two completely different things.