The knock sensor is a failsafe, not a prevention. Using the knock sensor, the PCM is reactionary in pulling timing. It's not programmed to pull timing before knocking, only after detection. That's why this classic story of knocking only on throttle tip-in is so common.
And speaking of these engines being prone to knock and the knock sensor not being being introduced later, I'm sure a lot of the people who owned the 1991-2002 engines remember hearing spark knock well.
2011 Crown Victoria LX - purchased @ 37k miles
currently @ 100k miles
Dark Toreador Red Metallic exterior
Medium Light Stone interior