There is a logical reason for this. Pre meter is "line pressure" - which varies from quite low to reasonably high. Post meter is regulated pressure (very low).
Also, if someone of low integrity was allowed to shut off the gas before the meter, they COULD tap in ahead of the meter and use unmetered gas. Shutting off after the meter and tapping in, it is still metered (and paid for) gas.
Around here, there is no wire on the pre-meter valve, and the post-meter valves are generally "pre-appliance" - and inside the house.