It's definitely something that's a part of newer D&D, though it's debatable when it started. It was inarguably a part of 4th edition, I think it was here by 3rd edition, and there's even a case to be made that 2e was headed in that direction with some of the supplements.

Anyway, your dad was right. :P During 2e, that was still a big part of the game. It's part of the differentiation between "old school" and "new school" D&D. Whatever I think of any particular edition, I think both approaches are rad for different reasons. :)

It's just the mismatch of expectations that would be a problem. It sucks to die because you were expecting another epic set piece battle, and it also sucks to try to come up with a clever solution to avoid an encounter just to end up not doing much or getting railroaded.

Gary Gygax dungeons were infamous for the "there's 3 doors. Behind door 1 is a swarm of giant poisonous killer bees, behind door 2 is an insta kill trap and behind door 3 is a tunnel leading to a chest full of gold and gems" situation without any way to distinguish the doors.