>Whenever natural gas supply is turned off in the US, for any reason, only the gas company can turn it back on

I had a seismic shutoff installed at my gas meter and the plumber who installed it had no problem turning off the gas and turning it back on when he was done. (and then turning it off again to demonstrate to me how it worked).

He re-lit the water heater pilot light before he left. The gas company was not involved at all.