I suggestion for improving your reputation:

Since you said that you are vetting third parties for their privacy standards, I suggest a public blacklist of those not private enough.
This would both increase your reputation as well as acting as an incentive for them to change.

Plus, this could also act as an incentive for a greater amount of ACL-powered API (read "from" field = yes; read "subject" field = no…) and their generalisation.