It seems as though the "Illegal immigrant" tenants did the owner a favor by improving the property even if the improvement was not permitted. 

Some weeks our checks from criminal restitution payments exceeds the coin collections...Leasing the coin op businesses to hard working immigrant families was the best thing I ever did with these ventures.

Also, be careful with "fake I.D.s" - we have seen an unbelievable uptick with illegal immigrants, fake I.D.'

Some of the early immigrants would lift the foundation of the property and put in a downstairs apt.

The biggest problem you will run into is if you hire an illegal immigrant, or if the company you hire uses an illegal immigrant.

I am worried that Trump may lose, and Kamala will destroy the U.S. with inflations, her stupid policies that weaken the dollar, the immigration will continue, etc...

If 'none' is your answer, talk to your company's immigration lawyer.

Most of these duplexes were purpose built by German immigrants in the 1920s with the idea to rent out upstairs for extra income.

The upside is, if you can get something at the right price, it'll on-sell or rent quite easily, as the population is expanding rapidly.Apartments seem to be doing a return to popularity, again possibly because a lot of the immigration prefers these type of dwellings.

We are seeing growth from the energy boom as well as immigration.