It's proof of tampering. The stalling is an indicator that it's likely widespread. The lack of agreement to allow full forensic audits, coupled with the ongoing "maintenance" of machines, is reasonable expectation of covering one's tracks.

Likely, the only proof of widespread computer manipulation that can ever be proven will be because of the source of packet capture. IMO, that's presently the missing link - can the packet capture be validated as true. If so, that's that. Still waiting to see what's said on this topic.

Thus far, there's more than enough to suggest this should be investigated on a national level, and in select cases, taken to court. However, all of the stops seem to be in to try and prevent this. We shall see what happens.