[jrs580]

It's to my understanding that when the car senses a knock in the engine, it immediately pulls timing to alleviate the pre combustion problem.

My question revolves around how this works after a supercharger like the Magnusson or a Whipple is installed. Does the tuner (the person writing the tune) rely on the car to pull timing or do they try to push the timing as far as they can without causing knock situations? If you could put a well tuned blown car on the dyno and monitor every time it knocks, would it be often or just every now and again?

[urr2slo]

To put it simply, the ECM pulls timing as it is "tuned" to do so. That's from many different variables other than knock such as but not limited to IAT, ECT, Cam Timing, and TQ management.
In relation to KR, yes adding forced induction (esp PD) you will see an increase in KR. Specifically Burst Knock....or what it really is "Predictive Knock based on rapidly increasing cylinder airmass".
What a "tuner" is going to do is set the appropriate tables to allow max timing advance with NO or VERY LITTLE timing pull do to KR.
If you were to log your car stock, you will see that it pulls timing very often to KR. This is acceptable from GM. However a good tuner would never let as much KR timing pull as factory does, especially when you add forced induction. The cylinder pressures are far greater and actual detonation will have much higher damage potential when you have forced induction. The goal when KR timing pull is active, is to pull more timing than needed to correct the issue and add it back when safe. This allows max power, but safe power.
So basically, with a PD blower, you should only see it every now and then. Mostly as a predictive measure to keep the engine safe. But what you should NEVER have is audible knock.