One facet of the principles of preparedness is to simply turn away anyone that shows up needing your help.  On the day how difficult will it be to turn away loved ones who are truly in need, in spite of living their lives carelessly?  Having extras for those situations means that the impact on the lives for whom you actually made the preps for will be minimized.  Knowing that we will need extras for unaccounted-for-others will lessen the consequences for us and our families.  God calls us to be generous to the needy.  And even if we know they have been careless with their time and resources, if they are loved ones we need to plan for some of them to show up with empty hands outstretched.