[pfg]

This would be a violation of root policies and would certainly cause the CA to be distrusted nowadays. It would also be detected with a high likelihood due to HPKP (and CT in the future). The economics of buying a CA for this purpose don't make sense.

[user5994461]

You might have missed yesterday's news from Chrome announcing that the HPKP feature is being considered for removal.

[pfg]

The deprecation timeline is being synced with the rollout of CT and CT enforcement headers (Expect-CT). This provides roughly the same detection (if not prevention) capabilities.

[criddell]

Would it be a violation if a company or person were only using it to crack open traffic into or out of their network? On my network, shouldn't I be able to do just about anything I want?

[pfg]

It would be a violation to do it with Comodo's publicly-trusted PKI, yes. You can do whatever you want with a private root that's manually deployed to the clients within your network.