If this is so, then why don't you hold similar posses and sweeps to find bank robbers? Drug dealers? House breakers? Thieves? Murderers? Heck, even speeders on our highways and red light runners?
I live in Maricopa County and my house has been broken into a full five separate times, and my back yard has been burgled twice. I also have to show my ID and sign my name in order to buy legal over-the-counter allergy medication. It seems to me there are far better uses for your time, as a law enforcement officer, than trolling Home Depot parking lots for pleasant, smiling men who are willing to pick grapefruit for a couple of bucks on a hot afternoon.
I realize some of these things aren't in your jurisdiction, but that hasn't stopped you so far. There's no reason you shouldn't enforce the laws for the Phoenix City Police or Arizona Department of Transportation, same as you go for enforcing laws under Federal Immigration Enforcement.
It would be nice to see you enforcing laws that affect me, personally, as a constituent living in Maricopa County.
Food for thought.