Yup that's basically it. If you have some electronic device (like an Android or iPhone), you can go to some sort of "about phone" setting page and poke around for a licenses button that'll show you all the software that your device uses. It's just proper attribution.
I've done reverse engineering and found obvious illegally used GPL code in closed source projects, and they could (theoretically) get in big trouble for not following the license. (I anonymously requested their source based on the terms of the license, but the company threatened to sue for reverse engineering, so it's often not worth it)