Considering how easy it is to find videos showing how to hammer an RFID chip, I assume that many CBP officers are aware of these attempts as well. So, if an RFID passport (passport card, EDL, NEXUS, etc) cannot be read with an RFID reader, then it stands to reason that a CBP officer would inspect the document more closely. But then I do not really know how a hammered passport looks like... Maybe, Firebug will comment?