Even if they were completely open source how would you verify that they are using the same software on their servers? That the hardware is not compromised? Aud

Even if they were completely open source how would you verify that they are using the same software on their servers? That the hardware is not compromised? Audit reports? How trustworthy are they if Symantec was able to provide good reports for such a long time for their certificate issuance when things were clearly not ok.