I have seen well over 1000 underdash harnesses, and of those, I have yet to run across a burned and unusable pink resistor wire due to mis-use. I did see one incident where the harness was pinched to ground and a short is understandable.
I have created one incident in a 1966, using just a stub of a resistor wire in an attempt to bypass it and use the firewall plug. That stub did burn up within a month or two, which I believe was due to trying to handle the difference in voltage from the starter circuit and the ignition plug. Since then, all 64-5 to 66 modifications to bypass the resistor wire I have made do not use the firewall plug, but require the owner to drill or use another firewall hole.