I am buying from Tartan.
Yes, gas line rough-in is standard feature for some other builder like Urbandale, but not Tartan.
If I hire someone to do, will definitely hire licensed person/company who will provide warranty on their work.
But you are right, what if accident happened? sigh...
It is not a big deal for a licensed personal to install a gas line. There is no more risk than any other type of renovation. The gas line is installed at very late stage of house building any way. Haven't heard any new house were burnt down by faulty gas line installation.