Correct me if I have anything wrong. Federal money going to the building of the wall provides workers mancamps or housing subsidies while there.
If they are there some x majority of the time they can declare AZ as residence for the 2020 tax year. They can also register to vote in AZ. AZ has one of the lowest state unemployment rates at 8.9%. So they could be including wall contractors in various AZ statistics.
As a bonus Mc Sally may get some votes from wall guys.
I have no feel for how many potential votes might come from wall workers, but I could see that their interest is on keeping their jobs building wall.
Did you see that Sen McSally flew down to the Border Wall with the President on Air Force One? Always nice to have a spare pilot on board.