The majority of the time, open adoptions are simply verbal agreements between adoptive and birth parents to maintain contact. There is typically not concrete documentation of an agreement to openness, therefore the level of openness can change at any time, whether the decision is mutual or not.
Some states allow for legally binding adoption contracts that require a certain amount of openness. If you have an official open adoption contract, it is technically illegal to close the adoption completely. However these contracts are difficult to enforce, so even a contracted open adoption can be closed.
The decision to close an adoption should be made very carefully. Completely closed adoptions are often detrimental to both the adoptee and the birth parents. Adoptees frequently have questions about their biological families that will be difficult to find answers for if the adoption is permanently closed off. Closed adoptions also leave birth parents with questions about the well being of their biological child. These questions can deeply impact their grieving process in a negative way.
Even when safety is a concern and direct contact would be harmful for the child, semi open adoptions are an option. Updates can be sent to birth parents either from the agency that facilitated the adoption, or through a separate email address designated to this purpose. This way adoptive parents have the choice whether to share identifying information and ensure the safety of their child, while still maintaining contact should the adoptee wish to have it in the future. For a birth parent, knowing that their biological child is safe and well, even if visits aren’t possible, will help their healing process.
If the adoptee does not wish to have an open adoption, it is usually appropriate to respect their preferences. The purpose of an open adoption is to benefit the adoptee, and if they are not benefited by it, the adoption can be closed.
Closing an adoption is very rarely absolutely necessary, but is still an option for those who do not desire to continue their open adoption relationship.