Lies which arguably may be justified by circumstances which force them, for example lying to those who are considered adversaries, or outside the "social contract" which contains the liar and other human beings of her company. The outsiders, or those lied to, are held to be outside accepted moral bounds and as a result need not be treated with the honesty due to others. The problem lies in the grave possibility of error, or of acting out of paranoia and megalomania. The practice of grey lies also raises moral uncertainty over the relativity of truth and the justification for counter-deceit.
An instance might be a couple driven to seek divorce in a society where it can be granted only for adultery. They may see two alternative ways to be allowed to divorce: committing adultery or lying to say that there has been adultery, perhaps by enacting an incriminating incident. It may be argued that in this case the system which encourages dishonesty is much less excusable that the couple who lied. Some laws even require deception, as in certain states in the USA where criminal records officials are compelled by law to deny that certain felons have a police record when asked by prospective employers. Cases may also be made for legitimate deception in the detection of tax-evaders or counterfeiters.