The City of New Orleans should most definitely give tourists priority in rescue, absolutely. Just like the USA should give foreign tourist priority in rescue, they are guests, they do not know the 'laid of the land" and their safety is our collective responsibility while they are in our country. It has been this way for a long long time and that is how US tourists are treated in other CIVILIZED countries.
Were it not so, other nations would have their militray in New Orleans right now getting thier people out, just like the USA has gone into other uncivilized countries to get it's (and other nations) people out.
Many are also missing another obvious reason to get the tourists out. Most need no further government services. Get them to an airport and they go home or elsewhere.