As for Form I-864, it is a contract between the U.S. government and yourself, where you give your promise to support the potential immigrants if they are unable to do this now or in the future. At least one of several possible criteria have to take place for your responsibilities under Form I-864 could end.
Liabilities of the Sponsor Under Form I-864
Form I-864, Affidavit of Support, is a lawfully implementable contract. In this case both the government and the immigrant who is sponsored have a possibility to take the sponsor to court if the sponsor can't provide appropriate support to the potential immigrant. Additionally, there's a possibility for the immigrant to leave his job and sue the sponsor for the support provided. Consequently, it is extremely important to trust the potential immigrant. http://www.coloradostar.com/newsr/8728