After a few entries with MDAC, I noticed they stopped asking any questions. For some reason in KLIA 1 they would always ask me how long I am staying and half of the time ask for a return ticket and at in KLIA 2, just occasionally ask a few questions, but never request proof.

I don't know if it's the MDAC or the fact that I have about 20 entry stamps from them in the last 2 years (typically 1-3 weeks visits and some same/next day transits).