keeveek: It's not so simple. If GOG is a business, even by distributing some games for free, like Elders Scrolls: Daggerfall, they make much publicity, and bring potentially customers. It might be treated like making profit by court, actually.
JudasIscariot: Profit by association?
Seriously speaking, I have to agree with keeveek's statement since freeware is different on the user end and a company end.
Profit by free advertising and public exposure. If GOG would host a freeware games without consent, I would handle the case, easy money. Actually, it would be so "legally stupid" that the lawfirm that is advising GOG would be liabel.
Whenever you make a profit of somebody else work, you better have a legal agreement with that person.
Gremmi: I think people in the thread need to clarify if they're talking about morality or legality. Games that are 'abandoned' aren't legally okay to download. I'm also wondering where the Gabriel Knight devs have said they're abandonware. Last time I checked, Jane Jensen was extremely happy that they were being sold again.
The devs usually also don't have the power to "abandon" the rights, because they made the game for a company. Even if the dev holds some of the copyrights (like name, character, story) they usually don't hold all the rights of the game.