Clinton sat on the Armed Services Committee for six years. She sat on the Commission on Security and Cooperation in Europe for nearly eight years.
There is zero chance that she didn’t recognize classified material.
But, as a follow-up to your email, I’d like to know if , while acting as a carpet-bagger Senator from New York, did Hillary Clinton use her own email account, or did she use the one provided by the government? That might have had the security training.
I worked with classified material up to Top Secret for 24 years. As a proposal coordinator for a major aerospace firm I was often handed material up to Top Secret (but totally unmarked as such) generated by engineers and scientists. I was expected to handle, control, and mark such material appropriately from the moment it came into my hands. Citing material not marked classified as an excuse to mishandle it, and even compromise it, especially coming from the top executive in an agency, is utterly ludicrous and indefensible.