Gog give you an offline official pre activated game installer, so you can install your favorite game everywhere
you don't need an account, software or the internet to play and enjoy and that's great
but as we can see, anyone can illegally share these copies on the internet, so the others can have it
and that's may be a problem for gog itself who do all of that to respect gamers and make them happy
and discourage devs to make their games available on gog platform
so I have an idea, just an idea, doesn't have to be a good or great idea or even a good solution to the problem above, the idea maybe even bad I don't know
my idea is that every gog installer should have a unique key associated with the owner account
and that will give as the following
1) the installer will not begin the installation process without entering the username and password of the owner account and also don't need an internet connection to be activated
2) if someone download a game he own it and give it to a friend who also own the game on gog too, then he can also enter its gog account username and password to activate the installer
3) every installer have the unique key associated (or refer) to the game owner account, so if the owner decided to illegally distribute the game installer then we can use the installer unique key to know who exactly is that person and deactivate his account

If you want DRM move over to Steam. We don't need this here nor do we want this here.

No DRM on GOG!

Here we go...
Out of curiosity, what makes you think someone wouldn't circumvent these measures? Piracy will always be a thing and more often than not they have it better than paying customers. Just look at what big companies do nowadays in order to prevent illegal copying, distribution and the like. In the end, who gets the short end of the stick? It's gotten to the point that if you wish to just play a game you have to jump through several hoops. The customer is and, at this pace, will always be on the losing side.
So no, I can't say that's a reasonable idea, quite the contrary.

Yes, it's a very bad idea.

Weirdly enough I've already stopped buying on gog because the small amount of DRM already in the store is too much for me but I could live with this idea. Provided it always worked, never needed an internet connection after the download and never prevented me from doing what I want with games I've bought. I imagine it would be more trouble than it's worth though to actually get it working with custom installers for everyone and would probably get cracked anyway.

What SpeedBo said above. ^

Your idea just can't work. If an user has to enter their username and password to start the installation, there has to be an authentication. Tell me how the installer will validate the information typed without Internet access. Smoke signals? Battle Drums? IP via Avian Carrier?

Alright, then it HAS to have Internet access. Congratulations, you just "invented" Online validation (DRM) by another name. Might as well start counting how many times this installer was used and limit it to 5 at this point...

such ideas have been discussed here over the years, as i remember. in conclusion: those who wanna buy, will buy. those who don't, won't. its not a matter of protection.

DRM apologists never understand that such shitty half measures like a key don't stop piracy, steam don't stop piracy, epic don't stop piracy either and we know that DRM free games can sell really well already so why worry about a few bad apples when the ones who spend their hard earned money is on harsh receiving end of that crap.

Piracy is also often a response to scummy behavior by devs and publishers trying to fleece you not to mention that a large amount a devs already treat paying customers for drm free copies worse than steam suckers.

The thing that stopped me from pirating games was discovering that gog sells them DRM-free. I've literally paid for games on here that I've previously "acquired" for free.

So you want to add DRM to DRM-Free offline installers?...

...that's easily defeated simply by repacking the post install game folder into a custom installer / zip file?...

...as cracking groups already do anyway with cracked DRM'd Steam games?...

Not sure you thought that through. The reality is whilst GOG installers are easily pirated, when the same game launches on both GOG & Steam at the same time, it's still the cracked Steam version that noticeably gets the most torrents, ie, GOG offline installers actually add very little to mainstream piracy.

that is hardly drm , if that is drm then , logging in gog to download your game is drm too

why this wouldnt work
1. you change your pw , but your downloaded installer will still have the old pw
2. gog would need to make personal installers for everyone, while that is doable i hardly see they would implement it
3. if somebody want to share illegally they would just install the game, then pack the installed files as they wont have any security in them and share that, as far as i know they already doing more with removing drm-s from installers and repacking the games
4. probably writing a security removing tool for them for the installer wouldn't take more than a few days

from these i hardly see the benefit his idea is your pw and acc name would be incorporated into the installer at least its hash , so entering your name+pw could be verified locally

You're lobbying for DRM on gog. That is a very bad idea.

Nevermind...never feed the trolls *slaps self on wrist*