I would say that you are not an engineer until you've both obtained the aforementioned peice of paper AND done something with your tumescent engineers forebrain.
That said I do think that there are a few exceptions to the rule, Dean Kamen for instance. Another good one is Bill Gates who, if I'm not mistaken, dropped out of college to start microsoft. I'd consider him a software engineer. Not a GOOD software engineer but...
Astronouth: You've just become some sort of pariah in the FIRST community. I'd apologize, a lot, fast.