The authors evaluated their system on a set of example sentences compiled from the MML, whereby highly conventionalized metaphors (or dead metaphors) are taken to be negative examples, reporting an accuracy of 0.58.
krishnakumaran and Zhu do not deal with literal examples as such: Essentially, the distinction they are making is between the senses included in WordNet, even if they are conventional metaphors, and those not included in WordNet.