Document Updates default to "private to my company"

[#1]

Would like the ability to set default Update settings to "private to my company". We are an in-house marketing agency and have been working to bring our clients in to proofing but discovered any updates that were made on a document/proof are visible to the client. We are trying to remind everyone to check off the private to my company BUT if they forget we don't notice until the client comments on a thread they shouldn't see. It would be nice to have a setting we can select to make Private the default for all updates and if we need someone outside our company to see it we can @tag them.