Yep good point RC refused classification is typically anything above R. So for example a porn store owner was just jailed for selling gay porn http://www.abc.net.au/unleashed/stories/s2927840.htm . RC != childporn and is quite broad, so if it is the bar quite a lot could be filtered and caught up in it. I'm sure some content would definitely be RC on youtube for example and with the general malaise of large swathes of the public service IT; I wouldn't put it past a ham fisted approach that catches up quite a lot.
Was this on your connection? AFAIK none of this is blocked and no one was actively filtering. What ISP are you with?