Reading the online docs (login required) on Adding attributes to the navigation index attributes are made live by clicking the red dot next to an attribute name - you then need to perform a full re-index.
If an attribute is not live then does this mean using it as part of location query (below, componentid is not live) will just not return any results?
fh_location=//catalog01/en_US/publicationid=tcm_0_72_1/componentid=tcm_72_55653_16
Having discovered that componentid is not live in our system and I need to query by it I don't really want to reindex over 6000 pieces of XML just to make this attribute queryable!