A) Everybody is "allowed" to lie. Research shows that most everybody lies dozens of times per day, just as part of social interactions. Plus, I really don't care who lies amongst their own group. Christians can tell each other just about anything they want.
B) My point is that christians have, as one of their Ten Most Important Things Not To Do, an edict against lying. However they do it all the time and pretty major ways. So that makes them hypocrites. Even if you say that The Ten Commandments are in the "Old Testament" and therefore only apply to jews, then there is still your Golden Rule, which was supposedly espoused by their supposed messiah. So, by lying, are christians saying that they think it is OK for others to lie to them in such a way. Is it OK to trick them into seeing something they weren't looking for? Porn, for instance? (Yes, hyperbole. Get over it.)
Personally, I lie as little as possible. However, I don't go overboard with the "honesty" by telling people exactly what I think of them all the time either. Every so-called "christian" I have ever met has been a major hypocrite. And I was a pretty involved christian for a while. That hypocrisy is one of the main things that started turning me off to the whole thing. (Now don't anybody start in with the "nobody's perfect, we're just forgiven" BS. I know, you are only forgiven if you are repentant. All of these people were unrepentant hypocrites so, by their own book, they aren't forgiven and aren't really christians. Plus, that wasn't the only thing that convinced me that it is all BS.)