Factorio devs once put out a blog post about game key stores. Essentially, they were running into the issue of people buying factorio keys with stolen credit cards and then reselling them for cheap on G2A or whatever. Then the credit card would get identified as stolen, charge backs would be issued, and bank fraud departments would get involved. As a result, the factorio devs were actually losing money from stolen credit card sales.

Of course, factorio is in a somewhat unique position of never putting the game on sale, so if you’re getting it cheap it’s probably from some dude using a stolen CC.