Why mutual awareness is not a control
Both parties are competent and both are paying attention, which is exactly why the arrangement feels safe until it is not. An operator reversing with a raised load, a cleaner stepping out from behind racking, poor light at the end of an aisle and background noise from a scrubber remove the conditions mutual awareness depends on. The failure mode is not carelessness; it is an ordinary sequence of events.
That is why the arrangement should not require anyone to make a judgement in the moment. Time or space separation removes the need for it. Where neither is fully achievable, the arrangement should reduce the number of moments requiring judgement rather than relying on both parties getting each one right across hundreds of shifts. Sites that treat a near miss as a reporting failure rather than a design signal tend to keep the arrangement and lose the warnings.
