They’re probably not illegal. They are probably some of the hordes from Obama’s freedom-trains from central America in the past few years. As far as the politicized US Government, DOJ and particularly the DHS is concerned, they have all the right papers, and certainly you want get any promotions in the agency by going after them anyway.
I work indirectly with many of these guys, showcasing my company’s construction products on jobsites. It seems many of them are here on work permits and are legal. Of course, many, many are not legal too.
Baloney....they are PROBABLY illegal...with illegal SSI numbers.
From my experience, generally the leader of the team is legal and speaks at least reasonable English. The rest speak no English and that gives them away.