We had two DMs who switched off with the adventures. One of them has a more modern storytelling approach to gaming, even though he started back gaming back as a kid in the late 70s (this was a nostalgia trip for him), while the other one, while young (early 20s at the time), had been raised by grognard parents and who went very much by the 1e book. We did manage to do things like teaming up with the slaves, but that was mostly, I think, because it was the older DM running at the time. And as I said, if we had been told this was out of character for the giants, it wasn't said in a way to make much of an impression.
The younger one is actually the one who stopped gaming with us first, since he had an opportunity to go play in more old-school games and there would be a schedule conflict. When that happened, the rest of us, older DM included, decided that was a good point to stop playing in the series.