HawkOpen separates Apple’s privacy proxy opens (R-OPEN-APPLE) from other opens and counts them as machine or proxy opens, so they do not inflate the observed opens. That removes false opens, but it cannot add the real ones that Apple hides.
Clicks are a better signal but not a clean one: company security filters also click links. HawkOpen rates each click with its own rules and classifies a click as likely human activity only with signs such as a visible browser page on a home or mobile network. Replies, available on the Pro and Business plans, remain the strongest signal.