I asked this question in law Stack Exchange
Basically, rather than simply prohibiting all sex with anyone under 18, the laws prohibit
Every one who deliberately commits violence, or threat of violence, forces, does tricks, tells a series of lies, or persuades a child to do, or let obscene acts be done, is subject to penalty of 15 (fifteen) years at most and 3 (three) years at least and fine of Rp. 300.000.000 (three hundreds millions) at most and Rp. 60.000.000 at least.
Notice that there is some penalty of 3 years minimum. For comparison, murder in Indonesia doesn't have minimum penalty and is usually sentenced to 10 years.
The law is strange because it contains phrases that suggest non consensual activities but then followed by consensual "persuades".
If my understanding is correct, basically, anyone that say, grope the breast of a 17 years old girl is subject to a minimum of 3 years sentence irrelevant of consent while anyone else that murder that girl may get say 10 years in prison. So it's kind of weird.
The phrase prohibiting persuade there means consent doesn't matter.
In fact, some expatriates express the confusion by stating
"The exploitation" and "persuasion" angle is not very clear to me. So sex with a girl above 15 is legal unless you "exploit" or "persuade" her to do so. Can anyone shows actual court cases?
It seems that actual court cases for this sort of thing is very few. https://www.livinginindonesiaforum.org/forum/general/laws-visas-money-matters-and-documents/52502-age-of-consent
How can anyone have sex with anyone else without persuasion (or coercion, or tricking?). Does whoever create the law want to prohibit all sex with anyone below 18 or there are some such sex that's legal?
If they want to prohibit all sex with anyone below 18, then why don't they just say, all lewd acts with anyone under 18 is prohibited?
A bit of background: Many people in Indonesia, are married young. Most marriage is informal. So they're not legally married but they hire some religious leader to marry them. That is between 15-18. Also many massage therapists, LC, or even sex workers are below 18. However, enforcement for this law is very rare. I cannot easily find court cases, nor do I know how to.
I am not interested in having sex with anyone under 18. I am just curious why the law is written in such ways.