"We will not use your Inputs or Outputs to train our models, unless: (1) your conversations are flagged for Trust & Safety review (in which case we may use or analyze them to improve our ability to detect and enforce our Acceptable Use Policy, including training models for use by our Trust and Safety team, consistent with Anthropic’s safety mission), or (2) you’ve explicitly reported the materials to us (for example via our feedback mechanisms), or (3) by otherwise explicitly opting in to training."

As for defending against a data breach, Anthropic hired a former Google engineer, Jason Clinton, as CISO. I couldn't find much information about the relevant experience at Google that may have made him a good candidate for this role, but people with a key role in security at large organizations often don't advertise this fact on their LinkedIn profiles as it makes them a target. Once you're the CISO, the target appears, but that's what the big money is for.