With the P contamination of homes on the increase don't you think it's time the landlord was given the chance to protect his/her asset from people bent on their own destruction?
I think it's time for "drug-free" tenancy to be put into their agreements, along with a clause that gives the landlord authority to carry out random testing for P use and kick them out if it's confirmed.
If the person wanting to rent the house has a problem with that, so be it, go find some other place to rent.
The P users who own their own homes can do what ever they please but they'd better be prepared to take their contaminated houses to the grave with them because no one will want to buy a home contaminated with that filthy drug.
Hopefully testing houses for P use will become more high tech and easier to carry out, so a random check does not inconvenience the tenant.