Chris, I think you misunderstood my remarks. In no way was I suggesting that you or anyone should do or not do something. Work on whatever floats your boat -- that's fine with me. My apologies if I inadvertently offended you. Certainly that was not my intent.
It is great that you have found a fix with KM but Iād like to mention an alternative that does exactly what you are needing. I use the Karabiner software which is used to stop or remap keys. I have configured it to stop CMD+W when specific browser tabs are active (like Gmail) or require me to press CMD+Q twice quickly in order to quit the browser. A single CMD+Q is ignored.