Yeah, I played this a few weeks back, and since this is an old school dungeon, and all the DC's are so high, it is entirely possible for everyone to fail their perception checks and make the dungeon unpassable, or even just have them die because they are stuck and can't leave, but can't find the thing they need to move on. That isn't fun.
So, I give an auto succeed option. Rations will be a big part, and eventually, they'll just starve to death if they don't have them unless they have other plans, so for the cost of 24 rations, they can auto succeed a perception check to keep the game going.
However, that also means I'm not going to prompt perception checks. They either make them, or they don't.