Very vulnerable to what? Not any force currently in existence. To even make the OP's premise work you need to invent a fictional opponent.
Quoting Amjads post here:
Red, commanded by retired Marine Corps Lieutenant General Paul K. Van Riper, adopted an asymmetric strategy, in particular, using old methods to evade Blue's sophisticated electronic surveillance network. Van Riper used motorcycle messengers to transmit orders to front-line troops and World War II light signals to launch airplanes without radio communications. The Naval Simulation, Joint Semi-Automated Forces (JSAF) had neither a sophisticated electronic network nor the modeling of WWII lights at the time of MC-02 according to the developer of the JSAF simulation; Mr. Guy Purser, Director, Modeling and Simulation, NWDC.
Red received an ultimatum from Blue, essentially a surrender document, demanding a response within 24 hours. Thus warned of Blue's approach, Red used a fleet of small boats to determine the position of Blue's fleet by the second day of the exercise. At approximately the same time that Red had located Blue forces, operators of the Blue naval simulation were directed incorrectly to turn off all self-defense capabilities by a senior Naval Officer who was not in command of the simulated forces nor current in the scenario. In a preemptive strike, Red launched a massive salvo of cruise missiles that destroyed sixteen warships while the JSAF simulator operators sat and watched without responding defensively or offensively. This included one aircraft carrier, ten cruisers and five of six amphibious ships. An equivalent success in a real conflict would have resulted in the deaths of over 20,000 service personnel. Soon after the cruise missile offensive, another significant portion of Blue's navy was "sunk" by an armada of small Red boats, which carried out both conventional and suicide attacks that capitalized on Blue's inability to detect them as well as expected.;[1] again it should be noted, the JSAF simulation did not at that time have the suicide behaviors modeled nor the damage models of interactions of a small boat impacting a ship.
At this point, the exercise was suspended, Blue's ships were "re-floated", and the rules of engagement were changed; this was later justified by General Peter Pace as follows: "You kill me in the first day and I sit there for the next 13 days doing nothing, or you put me back to life and you get 13 more days' worth of experiment out of me. Which is a better way to do it?"[2] After the reset, both sides were ordered to follow predetermined plans of action. This was done to achieve the real goals of the exercise and experiment which was to stimulate command and control systems which determine the outcome of the scenario.[3]
After the wargame was restarted, its participants were forced to follow a script drafted to ensure a Blue Force victory. Among other rules imposed by this script, Red Force was ordered to turn on their anti-aircraft radar in order for them to be destroyed, and was not allowed to shoot down any of the aircraft bringing Blue Force troops ashore.[4] Van Riper also claimed that exercise officials denied him the opportunity to use his own tactics and ideas against Blue Force, and that they also ordered Red Force not to use certain weapons systems against Blue Force and even ordered the location of Red Force units to be revealed.[5]
This led to accusations that the war game had turned from an honest, open free play test of America's war-fighting capabilities into a rigidly controlled and scripted exercise intended to end in an overwhelming American victory,[4] alleging that "$250 million was wasted".[6]
http://en.wikipedia.org/wiki/Millennium_Challenge_2002