I renewed my license the other day and I was really anxious after reading this thread for I might have a "hit that never happened." Thank God I didn't get a hit.
But I observed that yes, people really do get a "hit" and there were 2 sides of the coin that I saw. The first is some people, once the LTO personnel calls them and tell that they have a hit, they will just accept and scratch their heads. But there were 3 different women at the LTO renewal center in a mall that day who were really annoyed after hearing that they have a hit. But only one women really pursued in contesting. She's claiming that she knows the violation, which was swerving but it happened last 2010 and she has sent her payment for her fine via Metrobank. But the LTO personnel said she needs to call MMDA and settle it with them. She called the MMDA office right there but after she hangs up her phone, she said that MMDA needs her to present the receipt at the MMDA office. She even added that she was sick so going to Orense to settle it is truly a burden. After that she just left.
So based on what I saw, it is really possible that you will get a "hit" in their system which is either you have no knowledge about it or you know about it and paid for it but MMDA failed to record it and it will be very burdensome to settle it. Too bad if you don't have the receipt anymore since it happened way back, you don't have a choice but to pay again.