The thing is, though, once you're in the back room, they can fairly quickly determine if you were lying, and if you did lie, that itself will be held against you. Unless you have a very good explanation for why you lied—and do a lot of groveling—just the lie can be enough to deny entrance (even if the truth is innocuous).
Explaining a non-lie can be annoying as well, but not having lied is a much better position to start from.
Explaining a non-lie can be annoying as well, but not having lied is a much better position to start from.