I've had posts censored. At least twice.

But even so, I would bet good money that what happened in the case of the above "guest" is as Amos suggests -- because I had it happen to me twice yesterday. I posted twice yesterday and had the post not appear. I was lucky enough, one of the times, to notice and I was able to back my way all the way back to my reply box, hit "submit" again. It still didn't work the second time, but the third time (as they say) was a charm.