Tenant trying to live in garage

[Blake Salisbury]

We live in a duplex and rent out the other side. Our tenants that are renting out the other side are 3 people who rent the three bedrooms in the house. They want to bring on a fourth tenant and have him live in the garage to bring down rent. We have looked up city code and a garage is not considered a living space. We are already strongly against this idea they have but wanted to get some perspective. Would we have increased liability insuarance wise for having a tenant in the garage? Is this typically a fineable offense by the city (Portland if it is against code)? Would be curious to hear if anyone else has ever crossed this bridge...