Quite a bit of "barracks lawyering" goin' on here. What the heck, I'll add my two cents worth: For those of you who are enlisting, working on a commision, etc, refer to previous posts advocating telling the truth. If your big dilema when joining up is whether or not to tell the truth, then it's time for a gut check. TELL THE TRUTH! Every single time! If the transgression was minor, you probably don't have anything to worry about. If it costs you your opportunity, then so be it. Would you rather take your chances with not getting your shot, or roll the dice with potential disciplinary action or UCMJ fun? None of us are perfect, TELL them.
I'll speak from personal experience here, in seeing several of my troops getting denied their clearances; The DIA will uncover just about anything. Also,don't plan your actions based on whether or not you expect to ever get a certain clearance. When I joined the Air Force I got the standard "Secret" national agency check, never thinking I would need anything else. Four years later I was in a special duty assignment that required a clearance involving an investigation by a whole mess of alphabet agencies. Point here being you never know where you'll end up. Fess' up.