It doesn't seem likely, in my opinion, that anyone would be in a happy and dandy state when riots are occurring everywhere, even if mostly everywhere. They'd be preparing for the worst.
That is your opinion. When FO2 came, most thought that talking deathclaws were not just unlikelly but stupid, so? We also used to think that when the bombs fell, humanity went with them, save for the vaults. However FO2 introduced New Reno and FO:NV landed New vegas on top.. (Funny how New Reno tone, which wasn't well received at first became the foundation of FO:NV)
Back to our case: riots =/= anarchy, and almost certainly there were still people who supported the government and armed forces, starting from various loyalist/military factions(e.g. enclave) and their families, various people who benefited during war time or had a lot to loose, people fed on propaganda and those who wanted to believe in it, etc... and don't forget the big guys in power armor with min-guns that keep the peace (Considering that the Vualts could only hold 1% of the population, its most certainly that surrounding location were isolated and heavily protected, as seen in the trailer)