Last time, april 2014 when I left from STI, a guy controls ure ticket at the entrance of "passenger only". U queue up for the immigration booths. No one at the "pay ure overstay booth", so just walked up to the regular ones.
The lady was conversing over the booths with another employee. She didnt look at me or acknowledge me..... just stamped the outgoing date stamped onto my passport and waved me through......
Went through security and then had second thoughts. Explained to a security agent, he just laughed and said " mejor para ti !!"
In the end I did go back and explained to the same woman that I had been in the dr 6 months, why didnt she apply the overstay tax.
She was confused and thanked me warmly......and I paid the thousand peso overstay.