Maxperson
Morkus from Orkus
Suppose the party is using darkvision and there is no light for the wall to show glistening? Especially in 5e where vision checks are at disadvantage as well as there being a lack of glistening.100% this. Non-telegraphed hidden environmental details lead to player frustration, IME. I mean, give them something to gnaw on: “the wall glistens in places” or “there’s moss at the base of the wall” or “there’s moisture in the air here” or whatever. They still probably won’t connect the dots until they are asked to make a check to avoid slipping or, you know, actually touch the wall and realize it has slippery spots before they even start climbing.