The linked explanation is clear to me, and the double consonant rule actually does seem fairly consistent across English, now that I know to look for it. Thanks!
Unfortunately, the rule still leaves ambiguity between MUNCH-kinn-ing and munch-KINE-ing, but I suppose the ambiguity is much less if you're familiar with the normal pronunciation of munchkin.
A munchkin is someone who follows the letter of the rules of a game while breaking their spirit, someone who wins by exploiting possibilities that others don't see, reject as impossible or unsporting, or just don't believe can possibly work.
If you have done something that everyone around you thought would not work, something that people around you didn't do after they saw it work, please share your experiences. If you tried something and failed or have ideas you want to hear critique of, likewise please share those with us.