The FA is correct. It is true that the Indonesian government now requires all airlines operating in and to/from Indonesia to have assigned seats.
Here's an excerpt from an article about this:
http://www.btimes.com.my/Current_New...cle/index_html
"(It is learnt that) AirAsia passengers do want seating options as practised on AirAsia X flights. This is also in compliance with the Civil Aviation Authority requirements in countries like India and Indonesia," Fernandes said.
Also, Air Asia has discontinued express boarding because all flights (QZ, AK, and FD) now have assigned seats.
Article.