You are not limited to only two resident ID's per home. A "green" resident ID is issued to anyone listed on the deed, in other words the owners. If three people own the house, then three people receive resident ID cards. The "blue" card is for non-owner residents. That is people who live in a home on a permanent basis, but are not on the deed. A non-owner has to prove residency before the card is issued and it has to be renewed every three years.