Have you ever got your credit report from Experian (or the other one, can`t remember the name)? It`s the address that is searched via their database so there is some truth in that.
The address is searched, but only for the person applying for the credit.
If Joe Bloggs and Fred Smith lived together at 123 Anywhere Road, and Joe Bloggs applied for a credit card, they would search Joe Bloggs at 123 Anywhere Road. Anything Fred Smith had got listed at this address would not be shown.
However if Joe Bloggs and Fred Smith had a joint account or mortgage or similar, then they have a financial association and what one person does will affect the other.