Resignation letters are lagging. The load shows earlier: a rise in single-day sick leave on the same roster line, a cluster of shift swaps that always move work onto the same two people, and training sessions that the same names skip.
None of those facts prove someone will leave. They prove the roster is already borrowing from a small set of bodies. Borrowing is a capacity event. Treat it as one. If you write a culture essay first, you will miss the Thursday when overtime becomes the unofficial relief ratio.
In the Roster Integrity Clinic we overlay paid overtime, unplanned leave, and published shifts. Where they stack on the same names for six weeks, we do not start with a survey. We start with whether the demand clock is honest. Surveys can come later, when the hours are not lying.
This is not surveillance theatre. It is the same courtesy you would want if you were the person covering everyone else’s gaps. Publish the load. Then have the human conversation.