Natural gas lines do corrode. I've had Chambers and other brands. All of the lines do corrode over time. In fact that is what does them in eventually and none of ours were ever underwater.

There is also the lack of an oxygen depletion sensor to shut off the pilot light if the flow of gas is interrupted. There is a reason why ventless gas heaters were required to have an oxygen sensor in 1980. Stoves are no different.