It’s a lie to just blanketly say “there is no longer any danger of accidentally leaving a gas range open with no flame.” Yes flame failure detectors exist, but (in the US anyway) there is no regulation requiring them, and is usually reserved for the higher end models of modern stoves. The vast majority of existing stoves have nothing more than a simple valve and nothing stopping it from being left open and unlit.

From propaneHQ.com. “It is important to note, however, that if you smell propane at any time in your house, you should take it seriously and take appropriate safety measures.”. Dude you should not just be getting used to the smell of propane. Ferrelgas, Amerigas, & Foster Fuels all say if you can smell it, it is either empty or leaking, but it needs to be shut off either way.