See my replies with the FAM document excerpts.
Renunciation cannot be done by parents/guardians on behalf of children/wards
children under 16 are presumed not to have the requisite maturity to renounce citizenship.
O was only 7 years old in 1968.
http://www.unhcr.org/refworld/docid/3ae6b4ec8.html
Article 7.
(2)With the exception as mentioned in para 1 the foreign woman who marries a citizen of the Republic of Indonesia also acquires the citizenship of the Republic of Indonesia one year after the marriage has been contracted , if within that one year her husband does not make a statement as to release his citizenship of the Republic of Indonesia.
Since Lolo did not renounce his citizenship SAD, in the eyes of Indonesia, became an Indonesian citizen in March 1966. This is automatic.
Another link that shows that this is an automatic action.
http://www.expat.or.id/info/familylaw.html
"If the foreign wife has not made such declaration to opt, she will nevertheless acquire Indonesian nationality after the first year of marriage, provided that the Indonesian husband has not in the meantime renounced his nationality. "
So how does the entire family become Indonesian citizens but the child not? It fails every logic test.
In all likelihood Obama was a legal, 100% Indonesian citizen - until 1971.