The CP pin is shorter so that when you unplug the cable, it disconnects first before the power pins. So it's part of the design of the plug and mandated by the IEC 62196 standard. That split-second gap is enough for the car and charger to detect the lost signal and cut the power before the main pins actually separate. No live pins, no arc, no danger.

Plug it in, it works the opposite way CP connects last, so power only starts flowing once everything is properly seated.

Simple rule: CP breaks first, connects last. The pin length enforces this mechanically, no software needed.