One of the especially irritating apologetic excuses I've seen offered by believers in books and in my conversations with them is what I call the 'Dennis Nedry Defense.' Any fan of the film Jurassic Park will remember that Nedry was the computer programmer who shut down the park to try and steal the dinosaur embryos, only to meet his end in the jaws of a Dilophosaurus. When the park administrators attempted to override Nedry's actions that shut down park security, they found themselves locked out by a password-protected defense that repeated, "Uh uh uh, you didn't say the magic word!" The Dennis Nedry Defense (DND for short) is when Christians argue that inconsistencies in the bible can be harmonized because 'it doesn't say the magic word.'
As a specific example, take the inconsistencies in the empty tomb appearances. Mark's gospel says Mary Magdalene, Mary the mother of James, and Salome were at the tomb. Matthew's says that Mary Magdalene and "the other Mary" were there. Luke's says that Mary Magdalene, Mary the mother of James, Joanna, and "others" were present, and John just mentions Mary Magdalene. The DND of these passages often notes that none of the verses say that ONLY those women were there, so it could be that all of them were there. In this case, the magic word is "only."
Typically, I respond to such claims by commenting on the unique agendas of each gospel author and how harmonizing their stories disregards what they were each trying to say and creates a theoretical fifth gospel that is unlike the other gospels, as Bart Ehrman has remarked. While this is a good criticism, I think there are bigger problems with the DND. For starters, is it really reasonable to expect that the gospel authors would've written "only" even if they knew for a fact that no one else was there? Think about when you tell a story and describe who was present. Think about when an eyewitness gives testimony in court and describes who was present at the scene. Do we usually say, 'Johnny, Jim, and Jack were the only ones there,' or do we just say, 'Johnny, Jim, and Jack were there'?
We may qualify that those were the only people there when we're pressed on the issue by someone, like a lawyer, but I think most of us can recognize that we don't always do this even when we know that only those people were present. We may not initially see a reason to clarify that detail or it may just slip our mind. Yet we also tend to presume that, when describing such things in certain contexts, our audience will rightly assume that we mean 'only,' though we may not actually say it. When someone asks who was in the car with you, most people will simply say, 'Dave and Donna,' presuming that it will be understood that they were the only ones present. What apologists are asking us to believe is that you are omitting another person who Dave might mention, and you both expect the audience to harmonize your testimonies to get to the truth. Is that not a little absurd?
On that same note, a second problem with the DND is that it relies on the silence of the text to speculate about possibility. I've pointed out before that the overwhelming majority of apologetic arguments revolve around possibility rather than probability (Pascal's Wager is the best example). Yet anything is possible to an extent, excluding logical contradictions like square-circles. Postulating arguments for possibility in the case of supernatural claims is worthless, though, like suggesting that Santa Claus is able to visit every house on Christmas because his sled travels at the speed of light; it's possible, but still no more probable than the whole Santa Claus story being a myth. This is why historians concern themselves with what is probable and why scientists conduct experiments to determine the likelihood of an hypothesis. Probability matters far more than possibility.
I already commented on why the silence of the text doesn't have to mean what Christians want it to mean. The absence of the word "only" does not imply that the gospel authors all wanted their separate accounts to be smashed together into one big mess in order for the truth to be understood. What a convoluted way for a supreme being to reveal its message too! I always try to be cautious in building an argument on the silence of a text, but I believe there is ample reason for recognizing inconsistencies as inconsistencies in the bible, and it seems to me that Christians are more likely the ones in error for using the silence of the text to twist variations into a comfortable, non-conflicting 'solution.' Inconsistencies are most often due to mistakes, especially among different authors, and it's only faith that guides a believer to harmonize things.
The Dennis Nedry Defense is something that Christians don't seem to accept from any other religion either. Islam has the doctrine of abrogation, or the supplanting of an earlier revelation by a later one that contradicts it. Muslims believe this is consistent with Sura 6:115 ("And the Word of your Lord has been fulfilled in truth and in justice. None can change His Words."), because it doesn't say verbal revelation, and perhaps abrogation doesn't necessarily mean god's words are changed. Christians see through this nitpicking attempt to maintain the Qur'an's inerrancy and so they reject the DND in this case. Yet the bible's inconsistencies are no less inconsistencies and the DND is still built on no less of a weak foundation. That apologists must resort to word games and deny the same games when played by other religions is another nail in the coffin of the inerrancy doctrine.