Earlier quoted context omitted.
Well, for what it's worth, if they get the virus while on a long tour of duty, by the time they get back they should be good to contribute to the herd immunity.
Only if they form antibodies. Studies have been suggesting that people who get it in asymptomatic form are not all forming antibodies - leaving them wide open to be future communicators of the disease.
Moreover, even if the percentage of such people were shockingly high (i.e. over a fraction of a percentage), you would need to conduct a huge survey to distinguish it from error rates on the tests themselves.