I had been called only once by another landlord. The tenants were paying but they had threaten to sue me multiple times throughout their one year tenancy because the unit didn't have air conditioning (never had AC, didn't advertise as having AC, and not required by law to have AC) and they claimed that it was inhumane. And then their parents emailed and called me from their ranch in Texas, threatening to sue me. So I had them out at the end of their lease term. When the new landlord called, I said nothing but answered his questions.
"Did they pay on time?"
"Yes they did."
"Did they cause damage to your property?"
"No they didn't."
They moved out the next week.
Just like @Elizabeth Colegrove mentioned, if I want these tenants out, why would I give a bad reference? So, now I always call the landlord before the last, ask the applicants for the address, and verify the tenancy with the other landlord to make sure I am not talking with the applicants girlfriend.