“those people without any obvious symptoms are contagious and cannot be tested; thus, the virus will continue to spread. So “the point is there is no way yet to determine who is sick until the symptoms manifest”
You are correct, with the possible exception to “cannot be tested”. They probably won’t be tested unless they have been in close contact with others who have it, but asymptomatic people can test positive for the disease.
But yes, asymptomatic people are always a danger in contagious diseases.
A lot of Asian Americans are in South East Asia for Chinese New Year right now. They will go back to their countries for 3 or 4 weeks once a year at this time. Most of them will be set to come back in about two weeks.
My guess is by that point there will be quarantines of at least 14 days for all of those returning. And if you are not a citizen returning, you probably won’t be coming at all at that time.