There is a large motive against confiscation of your home or some other private property as a shelter place and that is the disaster will come to an end - whoever does the confiscating is liable for any damage to the abode. As long as there is a socieity, there is liability, and lawyers... Your house is the only one left standing for 6 blocks, and the city moves a field hospital or shelter for 30 neighbors into your living room? Prepare to get a new living room when its over. No, authorities will first look to public places to use, then abandoned commercial spaces, third maybe tents - and between these they'll find what they need.

Within 20 miles of home there is an empty KMart, an empty GI Joes, and and empty Lowes mega-store, all cleared, all that is necessary is to flip the lights and heat back on. Meaning, you don't need too much imagination to find places before you start commandeering private homes. And the same goes for food and other supplies - tight for the first 96 hours, but after that most authorities can expect supplies to start coming in.