Sadly, as soon as this becomes common, the hoarders will do the same to avoid the shame/consequences. Fear makes people very very irrational. :(
One up them and include pictures on your sign of the people you are shopping for!
(Yeah, it's a cat / mouse game...)
Well it is a temporary solution at least.
I agree with this 100%. People in South Africa are panic buying. So these people think you are taking the groceries to your cave. Get a sign and people can read for themselves.
Double benefit in that it might encourage others to help too.