San Francisco tenant wants to add roommate. Unsure how to proceed

[Barry Kwan]

Hi BiggerPockets users,

I have a pre-1979 built duplex rental property in San Francisco, California. Currently, in the COVID-19 pandemic, my 2 tenants of 4 years living in one of my 2-bed units had some dispute and one of the tenants on the lease is moving out. Another tenant wants to stay and informed me via email that she wants to add a roommate and wants to find it herself to pay for a portion of the rent. In my opinion, I wouldn't like her to add a roommate since she'll be finding one herself, unbeknownst to me of who the roommate will be. The only issue that comes up is if the current tenant leaves and this stranger stays there, I know issues will come up during eviction.

After reading the SF Rent Board rules, I know I'm not allowed to deny her of a roommate on the basis of creditworthiness, and I can only ask for a background check, and if I do deny, the tenant will request to the board on rent reduction possibly. Now hearing that, I definitely need money to pay for the mortgage and have determined it's okay for her to have a roommate. Now I just have to choose which three scenarios below, shield myself from worse case scenarios when dealing with courts--a nightmare process in SF. Which one would you choose if you were in my shoes and the pros and cons of it?

Three scenarios:

1) Have the current tenant as the sole master tenant and have her pay me all the rent in full, with her dealing with gathering rent from a roommate I don't know.

2) The tenant might want to add roommate--unbeknownst to me who it would be--to the lease, and from that a new lease.

3) Refuse the roommate request, and have a possibility of tenant requesting a reduction of rent due to Rent Board rules.

Thanks!

Barry