Hello fellow LOTR gamers. I'm really hoping it's not true but do location, treachery, and enemy effects stack? For example a location card that has archery. Would 2 of the same location have double the archery damage I need to deal to my characters? Or a treachery that lowers attack and defense of my characters by 2. Would 2 of the same reduce my attack and defense by 4?

Unless it says otherwise, yes. As in your example two things with Archery 2 would mean you have to assign 4 points of archery damage.

Right, thank you.