Prolence: From the FAQ:
9. Can I enjoy my purchases both on my laptop and desktop computer at home?
Yes. We do not limit the number of installations or reinstallations, as long as you install your purchased games on computers in your household. So yeah, if you've got a render-farm in the basement, you might actually break the world record for the number of legal Witcher installations in one household.
However, if you think about installing your game on a friend's machine or sharing it with others then please don't do it, okay? Just to throw this out there, unless your friend gifted the copy to you with GOG's own gifting system, this applies.
This is the time I'm having and willing to put here, so take it as you may.
At least you provided me with an actual answer .