We were there in August and it was very weird. We parked at Downtown Disney and took a ticket and it said, first 3 hours free. So we thought, OK, we'll make sure we leave before 3 hours are up...which was no problem since we were only killing time before heading back to our hotel and then heading back for Goofy's Kitchen. So we left the parking lot 2 hours later and there was NOBODY manning the ticket booths...we just drove through (the gates were up.) We thought that was odd (time was about 6:00 pm or so)
We went back an hour later for Goofy's Kitchen and took another ticket. We could see that there was somebody in one of the booths now...so we thought...ok, maybe it's only at night that you have to pay. So we're finished at Goofy's and walking around DTD around 10 pm or so (close to our 3 hour time limit) and we drive towards the exit. The exit is JAMMED and we thought people were paying...but no...there was nobody manning the booths again so we just drove through (as did everybody else.)
Weird. And remember (though we didn't and ended up paying parking at Paradise Piers), that if you eat at one of the hotel restaurants, you can get it validated and get 2 hours (I think) free parking.