For the last security report I had to deal with for a client, the main vulnerabilities were reported against a Google site that was merely linked to from the clients site. Not PCI compliance, so more flexibility in dealing with their incompetence, thankfully.
They reported a number of purported (non-existing) "vulnerabilities" against said Google site that included that it stopped responding to their probing soon after they started hammering it with sketchy requests... They did, to be fair, point out that this could be a defence mechanism, but dinged it for preventing them from checking for other vulnerabilities.
At least I didn't have to explain why that one was nonsense - it was rather obvious to my client that the agency they'd hired were being idiots. It's not like it was difficult to see either - the domain name of the site they'd hit had "google" in it.