“In the US, wandering in on foot in quantity would be noticed.”
Pretty sure they wouldn’t all go in at one time. Their objective according to the government explanation is to be among the citizens without raising questions or suspicions. They wouldn’t be in groups as that would be noticed.
Unless they grow some hair before they do this, a crew cut on a guy would stand out. It’s also difficult for them to drop the sharp movements they have due to military training. They would tend to sit up straight in a chair, not slouch at all. Walking sharply is in their gut now, so that would stand out.
It takes many years to develop a force that can infiltrate enemy ISIS-type populations in our cities, the language, dialects and ‘trusted’ contacts being training item 1, the physical/appearance training would take a month.
If you were an Iranian or ISIS cell waiting for delivery of WMDs and instruction from above, the people you would trust to activate you would require much scrutiny, or you just got yourself renditioned. The experts remaining are what Jade Helm is probably going after. If you were W you might keep this out of the next president’s oversight, control or even knowledge.