You sum up morals very good.
I see topic of “charity when SHTF” very often, and I can say that in special situations doing charity is not good idea.
As you say there that people will expect more, you are very right.
One of the first thing to do when SHTF is to keep low profile, by giving food to the folks you are definitely not keeping low profile, you are saying to them “I have more of this home” and at the end people want more from you, and in the world without law they will try to take from you.
If you already want to give some food, then do that like you are trading it for something, even you do not need that, for whatever.
Jus to not make it like gift or charity, do not make it look like you can spare it.