I don't have to stop anywhere B4, any such construction site is governed by the bargaining agreement between the existing labor union and the contractor with the local union providing any and all such workforce. If you have any complaint about any workers being illegal rather than working under a temporary work visa, then you take your complaint to the local. But I really wouldn't recommend it.
But addressing your statement, all you have done again is issue an unsubstantiated allegation. We deal in facts here......