^ This...
used to do it while I was doing my last degree part time... hard work and not for the faint hearted... lots of Saturday nights sacrificed for night shifts... you earn like $40/hour on weekends when you take into account shift allowance and all as well... got to the point where I just couldn't do it anymore, plus I wanted to do my next degree full time, I was working up to 60 hours a week... told the call out manager to take a long walk down a short pier (he was a complete ass)...
Didn't know a white card was compulsory now, thought that was just a construction site thing...
I recommend doing the course for lollipop men at roadworks... get paid $25/hour, and just hold a traffic lollipop all day long, course is only a day long as well...