And then there's you have to keep track of the lies, and that most people prefer to think of themselves as not the kind of person who would ever, ever gossip -

And then there's you have to keep track of the lies, and that most people prefer to think of themselves as not the kind of person who would ever, ever gossip - which isn't the same as saying they don't. The moral consideration carries real weight, as you note; lying in a survival situation is one thing, but this kind of problem relatively rarely meets that standard. But even if the potential moral iniquity and certain hazard is entirely ignored, the policy as a practical matter simply cannot work for long.