I thought that was expensive, $800 is prohibitive!

Yes, these things are prohibited in any case, but tenants do them, and including them in your lease will help you evict when necessary.

Of course, a specific contract can prohibit assignment, but the law clearly allows it.You cannot advertise a property for sale unless you legally own it.

Also many cities that have ADUs prohibit you from renting out both units. 

Phoenix is not a market that is prohibitively expensive either.

update on this:    the rent control prohibition repeal ordinances (house and senate version) introduced for 2018 in the WA state legislature both failed to get out of committee.  

I believe this is a prime example of why a major tool in screening, background checks, are starting to be prohibited in some municipalities.If he's on a month-to-month lease, then end it once he ends up in jail and unable to pay you the rent.

I don't prohibit them.

You certainly can't prohibit them from owning a gun so I'm not sure there's a truly perfect and practical solution.  

Ken Min , the landlords are just trying to run a legal business but seem to be getting treated like criminals themselves .L.A just started a "ban the box" ordinance which reminds me of this , "Los Angeles City begins enforcement on July 1, 2017 of its Fair Chance Initiative for Hiring Ordinance that prohibits employers from seeking criminal background information prior to offering a job to applicants.