Yes. I got into this argument yesterday on another thread and don't want to rehearse it here, but the EO should have grandfathered people already traveling with valid U.S. visas. On green cards, if there is a specific reason for reopening the vetting on a particular individual, fine. But otherwise, a green card holder is a legal permanent resident of the U.S. and should be treated with respect. Trump's EO was over-broad. The very small number of people with visas and green cards already in transit should have been grandfathered -- again, unless there is specific information about a particular individual that warrants a review on a case-by-case basis.
The process of entering the US with a visa is not complete until the visa holder has cleared the final interview at the Port of Entry and has been admitted to the US.
Green cards can be revoked at any time and upon returning to the US the green card holder must still satisfy the customs Agent at the Port of Entry that they do not fall into a category of aliens not allowed to enter the US. I.E.: was involved in sex tourism with children or narcotic trade, etc.