Quote Originally Posted by danielxcutter View Post
I think it only provides a bonus to the related checks, and the compartment could have a very high DC to find and/or be concealed with magic.
In addition to a (relatively small) bonus it also allows any dwarf that get within 10 ft to make a search check as through they were actively searching.
However given how few skill points clerics get, and the fact that search is a cross class skill for them, it's pretty likely that none of them invested enough into it to discover the compartment if it is well made.