What's to stop them ending up with Iran levels of infection in a matter of weeks?
How would we know if that were already the case?
Americans without insurance don't go to the doctors as they fear financial ruin as much as they fear the virus.
If someone dies and they aren't testing how will they know what they have died of?
Who is keep a record of an unexpected rise in respiratory failure deaths in the US either nationally or by state?
The Trump administration doesn't want to admit a problem. They are as authoritarian in their desire to cover up or deny a problem as any tin pot dictator state.
We are unlikely to detect cases originating in the US in Europe now, because we have so many other cases. We are looking for cases from Italy, South Korea, Japan, China, Iran, Thailand, Cambodia, Laos and Myanmar. But not the US. So no one will know if a case has originated from the US.
It'll just be a case from an 'unknown source'.