Loosening the glow plug to start a high compression inboard boat engine was common once. In fact there were companies selling special long reach ni starters using a nut driver specifically to loosen the plug and engerize it and then start the engine and then tighten the plug back up. It may been have because the inboard boat engines had to be started with a belt around their flywheel which made it hard to start them. But I knew someone with a Mazda GLC that blew out (stripped) all of its fouir plugs when the engine was started and driven before the plugs were tightened down fully; gas blowby may have contributed to erosion of the threads and the plugs blowing out. The GLC engine had the plug threads trapped directly into the aluminum heads, not unlike some of our glow engines