The same way you do it digitally: add a thin layer of DRM that gives you legal protection, but doesn't actually do much on a technical level. Check a license key from the game drive in the same way you'd check the key of software someone paid you for, then let the code run on their machine.

DRM itself isn't a very good way of protecting media. The functional protections are almost nonexistent due to the nature of it. If you want to let someone play/watch/read content, you can't also make it magically impossible for them to just take the code/video/text, and copy paste it somewhere else. The only thing DRM does is give you the legal right to invoke the state as a way of enforcing copyright law against anyone who 'pirates' your work.

Any fraud that could happen likely wouldn't be stopped no matter what they tried. (or rather, if they did nothing protection-wise)

You don't actually need to. The people who want to buy your game will buy your game. The people who don't, just won't. That's not going to change by implementing artificial scarcity, people who really want it for free will find a way even if you try to stop them.