In a perfect world, true. But in my world, contractors dont give a rip about you or doing a job right. They just want to come in, over charge you, cut corners, and move on. not only from ones i've hired in the past, but also ones i've gone behind to fix the crap they got away with.
Running gas line is not rocket science, and if i'm going to pressure test and have it inspected, I'm a lot more comfortable with my own ability than someone else. I'm really just wondering to the logic of the science in running a 1" pipe that starts with one smaller. If i need to call the gas company that's what i'll do, but you come to a forum, hoping to get constructive advice to make sure you do something right. If you want to point me to the code i'll read that, but so far i haven't seen that kind of answer and dont expect i would.
Really, why even have forums if you're not going to be helpful. You can run people away from everything....Don't do your own plumbing cause if you have the slightest water leak, you'll attracked termites and bring your house down. Don't run your own electrical cause you could shock your self and die. Don't frame your own room cause if you don't propperly support it, you're house will fall in on you and you'll die. Don't try to insulate your self because if you don't account for moisture properly, you'll risk mold take over and die, not to mention termites, etc...