Still never seen it happen. It either takes a really freakishly long time, or... that's not entirely correct.
And even if it did, I'd just run the games directly from the folders they're in... I do that on my laptop on occaision if good ol' Windows is being slow as dirt again (makes me not want to load things much... usually makes me want to just turn the damn thing off really), the stupid thing. Makes me impatient.
Either way though I personally still wouldnt use GoG at this point, particularly with their screwball selection process. Too much chance of missing out. My thoughts on them have gone from "meh" to outright disliking them. Not fond of not being able to buy something because "Feh, we PERSONALLY dont like it or dont understand such-and-such type of game" or "it's too niche" or "ZOMG GRAFIX". Or because of a lack of caring. Or whatever other reason. I can understand the desire to do "quality control", but... considering they're refusing things that are of DEFINITE high quality (and I very, very strongly doubt it's JUST something like Cave's games... chances are, it's WAY more than that, with that type of policy), that, to me, is a big load of crap. Not about to support it. Instead I just recommend to friends that they buy from... absolutely anywhere else. didn't used to do that. Now I do.
Honestly, nobody has figured out a good way to do quality control yet. I'm thinking it'll be a LONG time before anyone does. Steam's "let everything in" idea can be annoying... or at least it would be, if it wasnt so easy to search for the ones that dont suck. So that's not been an issue. I buy games *really* frequently. I think I bought like 9 in the last week and a half (I was bored). The ONLY game purchase I've regretted in the last YEAR was Anno 2700 or whatever number it uses. 2070 was really good, that one was really not. But other than that? It's easy enough to sniff out the bad ones before buying them that I've not regretted anything else. Heck, I dont even know how to do the refund thing on it (and I'm too lazy anyway).
Though, one thing about the "always online" complaint always bugs the hell outta me: This is 2016. Most computers (as in, any that arent ancient) are basically online at all times ANYWAY (and if they're not good enough to handle Steam, or whatever, running in the background without imploding, they arent going to be playing much in the way of games as it is). When they ARENT.... way more than just Steam tends to break down. Particularly with the internet being so important nowadays. So I tend to not see the problem. And if someone's internet is so bloody broken that they cant get it connected.... they're not going to be buying from GoG or anyone else ANYWAY.
I will say though, I kinda miss the days when I could just buy games in boxes at stores. Though... that had it's problems too. I know people say "well if it's DIGITAL it's not guaranteed you'll have it later!" but at least digital games arent CDs that break if you look at them too hard. Makes them way more iffy IMHO. But there was still something satisfying about getting them in a box.