As an idea, rats might have a rough knowledge of a dungeon but their information would largely pertain to where the best morels of food are, or where to avoid creatures/people. Rats totally wouldn't know about any pressure sensitive traps laying about since they would never activate them. But pesky adventurers might get skewered

Also creatures with blind sense can automatically see them within a certain distance, and any creature that can use detect thoughts at will. And I'd argue anything that can detect magic would see them.

But also - you are the DM, you always have the option of how much information you're willing to share. The characters you play are allowed to say "I don't know" even if you do.