There's no danger in dollars being repatriated.
We should be more concerned with people accepting Treasury's as legitimate debt instruments.
And, that is spread worldwide. Not just oil countries.
More dollars chasing the same amount of goods equals inflation. Should the artificial demand for dollars come to an end, there will be a massive increase in dollars and an equally massive deceease in the demand for them. That equals hyperinflation- Weimar Republic time. The fact that we would also no longer be able to print money to buy oil would also suck I think.