In any disaster involving the loss of civil order, prepared people fend for themselves. Some definite psychology will arise then, and you need to plan NOW to deal with it.
The psychology is that the un-prepared will want to join you, and either remove your supplies by force, or sponge off of you, depleting those supplies quicker than you had planned, endangering you and YOUR family.
Dealing with the first instance is easy. In the S.H.T.F. scenario, you will defend your survival supplies as you defend your very life, because you WILL be defending your life. Deadly force is appropriate against anyone who would take your supplies. Do not hesitate to use deadly force, and use it against any and all who threaten you and your supplies, and use it IMMEDIATELY when the threat arises.
The second scenario is more difficult to deal with, and requires some pre-planning.
The plans should include a pre-printed paper handout which will become VERY important, for several reasons.
You may download that handout here:
Note that the handout is simple and to the point. You should allow the sponger to read it in front of you, while you maintain your distance, armed, of course, weapons visible but not pointed at the sponger.
After the sponger has read the handout, ask him/her if they are willing to fully comply. If they agree, you may issue your orders to your new subordinate crew/family. If they do not, cover them with your weapon and order them off the property and out of the vicinity (so much as you can make that stick).
See, this isn't that hard, but it DOES involve some philosophy. If you are to become the leader of a Clan, you assume the responsibility for those who have willingly joined your clan and sworn fealty to it. that means different things, but among the things it CERTAINLY means is that you would do well to have more food and water on hand than just you and your immediate family need. Maybe more arms, as well. Maybe more shelter capability, as well.
Whatever, but PLAN it!