I had a clash for ENGG1000 for the EET (electrical engineering & telecommunicatoins) option - the lecture cut into the tutorial.
It wouldn't let me enrol, and I had to ring them and they enrolled for me. The clash was only in like weeks 2 and 7 or something, so it's not that big a deal.
The lady on the phone from the EET office said that the lecture just wouldnt go for the extra hour even though the timetable said so.