If you refuse to ship out for basic training, this ties the commander's hands. For the Army National Guard and Army Reserves, under current regulations (Army Regulation 630-10), the only option the commander has is to process you for discharge. Chapter 5 of this regulation covers Army Reserve and Army National Guard. Under current regulations, this is the commander's only option, so if anyone tells you (including the commander) that you will go to jail, or be court-martialed, or anything else (other than a discharge), they are lying to you. You can safely ignore such threats.
Paragraph 5-2 of the regulation applies "when an enlisted Soldier ordered to enter on IADT (Initial Active Duty Training) refuses or fails to comply with the order. It is applicable to Soldiers who enlisted for the standard training option or for the alternate (split–training) option."
Paragraph 5-2b of the regulation states: "If an extenuating circumstance did not exist and the Soldier refuses to comply with the IADT order, the guidance counselor cancels the training reservation. The appropriate separation authority processes the ARNGUS Soldier for discharge from the ARNGUS and as a USAR. The USAR Soldier is processed for discharge under the entry level performance and conduct provision, AR 135–178, chapter 14."
The discharge must be characterized as an "Entry Level Separation," for "Performance and Conduct." An Entry Level Separation is not characterized. That means it's not "honorable," it's not "general," and it's not "Other than Honorable." It has no characterization at all.
So, how is this different from an active duty DEP Discharge (other than it's more complicated)? Well, an active duty discharge from the DEP is not really a "discharge," because it creates no military record. Recall that I said a person discharged from the active duty DEP can legally and morally state on any form that he/she has not served in the military. However, members of the Guard and Reserve, are entitled to drill pay, even if they haven't been to basic training, which means they were *IN* the military, and a military record is created, and filed at the National Military Personnel Records Center, in St. Louis.
That means, if you are ever asked if you have ever served in the military, you must (legally and morally) answer yes. This could possible affect future employment opportunities (some employers may put great weight on whether or not you "quit" the military, and other employers may not care, at all). It will also definately affect your eligibility to join any branch of the military in the future.