A real estate investor made a lease agreement with a tenant who operates late at night for a room on the lower floor of a rental apartment building that the investor borrowed money to invest in. Subsequently, due to noise and other reasons, many of the residential rental apartments on the upper floors became vacant and were foreclosed upon because the investor was unable to repay the debt.
There is nothing wrong with tenants who operate late at night, and you may be able to get above-market rental income from those tenants, but you should carefully consider the impact on other tenants when deciding whether to actually lease the apartment.