Dude, I would be the only plumber in town doing that, and it would scare me. Not because of the install, but because of what some other jackasss or HO may try to do later. I use CCST from time to time, and recently this month started using the yellow poly for underground.
But people are dangerous. Like gas grill stub outs on new homes. Everyone else leaves them capped outside on a new un-sold home. Not us. We install a valve, and regulator (IF needed) and cap the end of the line. I've had 5 calls the past few years of guys wanting someone to come check the gas on their grill, that its shooting flames 4 feet high, from them hooking it up themselves not knowing what they're doing. I could see that copper line getting tapped into for anything else but gas by someone else.
