It's not banned everywhere. There are some schools that still allow it. All the private schools in Adelaide still had it up until last year. I think the pig's head that someone from Sacred Heart brought to school may have contributed to its banning.
It's officially banned nowadays, owing to the practice degenerating into rampant vandalism on the part of less imaginative cohorts. In Western Australia they tried to sanitise it by renaming it "Activity Day" – now that's just lame!!
I recall (about 30 years ago now) my big sister spending a whole evening drawing red hearts on a roll of toilet paper, as did many others. Apparently a teacher's car was wrapped in this. I'm not willing to tell you what my school got up to. We were very nerdy.