Why is it so important to destroy radio reception in the vehicle?
Bypassing of signals by proper placement of capacitors is just plain good engineering design. Please explain why interference back into supply voltage is a good idea.
You are making an assumption, and it turns out to be incorrect
OP said he was connecting an MSD box. These are capacitive discharge. YOU DO NOT connect ANYTHING to the coil with a cap discharge ignition other than the output from the cap discharge box. That's the way they work, and that's the way they are wired. Adding a radio cap to a cap discharge system is simply going to discharge the ignition pulse from the box right to ground through the radio cap