Let me re-emphasize what John T. has said. The neutral is a "grounded" conductor and is allowed to carry current under normal conditions. It is referenced to "ground" at one point only.
The "grounding" conductor, also commonly know as the "green wire ground", "safety ground", or "fault protection ground" is not intended to carry current in normal operation. The "grounding" conductor is there to provide a low resistance path back to the power source ONLY IN THE EVENT OF A FAULT.
If you connect the neutral and ground wires at more than one physical point, then any current will split between the two conductors, negating the purpose of the fault protection conductor. Remember, circuit breakers and fuses take a finite amount of time to trip, and during this interval it is possible to have enough current flow to raise the neutral voltage to a level that can create a shock hazard. If you connect the safety ground to the neutral, you've negated the safety provided by the extra ground wire.
With regard to multiple distribution wires off the meter box not having ground wires, its common practice to treat each building as a separate distribution point and establish the neutral/ground connection separately for each building. Neutral is referenced to ground at the first panel in each building. As long as the power distribution systems in the buildings are never connected together between buildings, everything is fine.
Keep in mind that the resistance of a ground rod to physical earth is typically measured in the 10's of ohms. A short from the hot side of the power system to earth, or something in contact with earth, can carry plenty of current to kill, but no where near enough to trip a breaker. Circuit breakers (and fuses) are protection against fire, the safety ground (or the use of double insulated load) is protection against shock.
Ground fault interrupters provide additional shock protection by sensing the leakage current to ground and rapidly opening the circuit.
While the NEC may be written as "guidelines", its because the originating organization is not a lawmaking body. However, in every jurisdiction I've ever heard of either the NEC or something similar is the law.
Remember, be safe and respect something that's capable of killing you in an instant. Codes are there for a reason, and most of them make good technical sense.
Keith
PS...one of my job responsibilities early in my career was designing power distribution wiring for large RF communications facilities, so I do have some hands on understanding of the rationale behind the code requirements.
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Today's Featured Article - Listening to Your Tractor - by Curtis Von Fange. Years ago there was a TV show about a talking car. Unless you are from another planet, physically or otherwise, I don’t think our internal combustion buddies will talk and tell us their problems. But, on the other hand, there is a secret language that our mechanical companions readily do speak. It is an interesting form of communication that involves all the senses of the listener. In this series we are going to investigate and learn the basic rudimentary skills of understanding this lingo.
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