Gentlemen,
Most modern cars already have fail-safe system in place. My AUDI will pull timing back as far as needed to compensate for knock which will become evident in case of WI failure. It does it quickly and effectively. So I do not see a need for fail-safe systems on most new street cars. However, saying so, if motor if highly modified and operates very high boost levels timing pull back may not be sufficient.
This is the example of timing pull back due to knock. Collum marked as CF (Correction Factor) is a reduction in timing done by ECU based on high knock level.
