Markit wroteUnfortunately that really doesn't answer my question. Did she want to or have to? Could she have kept her old Indonesian maiden name?
See what I'm trying to tie down is if the Indonesian wife doesn't have to tell the authorities she's even married to a Bule why all the stress with pre-nupes and such like?
Markit, to answer your questions, yes there are many Indonesian women married to bules who do not inform the Indonesian authorities. They often take a passport from their husband's country while also keeping their Indo passport (which is illegal under Indo law), and also do not register their marriage in Indonesia, thereby avoiding having to change their KTP status to married (also illegal). The downsides would include the fact that both spouses would not be entitled under Indo law to inherit anything from each other (as they are not married), and any children would be viewed as illegitimate by the Indo authorities (so no rights under Indo law, including inheritance, and no passport). Also, the bule husband would not be entitled to get a KITAS or KITAP from the non-existent wife's sponsorship, and the non-compliant Indonesian could no doubt get into unpleasant trouble with the authorities in the possible, albeit unlikely, event the deception was revealed. Under these circumstances, a pre-nup costing a few juta Rp would seem to be the least stressful option...
Also, as far as I know (and have experienced) there is no hard and fast rule on changing names once married. Some women keep their family surnames, others adopt the husband's.