While all the people posting on this and similar threads, 100% of the focus has been on HD in the case of a few people coming into the home.
Twice in my life (while in the USA) I have been right in the middle of Anarchy. 1965 Watts Riots, and 1992 Korea Town Los Angeles Roddney King riots.
Here you had really masses of people into looting and just general destruction. Seed like LEO were more interested in arresting shop owner trying to protect their property, than the looters. There was no one to call.
The $64 question will always be:
1. How to defend, and the appropriate level of force to use against large groups of mostly unarmed people, included "children".
2. How to shield yourself from harm.
3. What do you use as defense.
When this descends on you, there is no advance warning to prepare. You have what you have. In '65 I had a 25/06 rifle and 12 cartridges, I used 1 to shoot a Molotov Cocktail just before it was thrown at my building. In 92 I had a 45 and 2 7 round clips. I used 2 rounds aimed at a foot each time. Both totally discouraged further advances by large groups. The option of just treating them like zombies may work, but when order is restored, you will have a long time to consider better alternatives, compliments of your government.
I was totally exposed had I had any serious armed opposition, and still do not have the answer for my home, but thinking about sand bags (smaller one, easy to move into a bunker position, and just build a storage box to keep them in.