With all the pikaness jazz currently happening, I have a query. What happens if someone's post is deleted by a moderator, before or after a match starts? Has it ever happened?

I've wondered about that myself. If you post an obvious violation, it will probably get modded before the prediction could be added. A borderline violation has the possible chance of being overlooked as a violation when it's put into the queue. And you could always mark your own message with a different account of yours.

Don't get modded, it'll make our lives easier =P
I remember it happening once, but not in an ambiguous situation (post was made and deleted on the same day). Players are individually responsible for the TOS-friendlyness of their posts.
It's kinda like cheating, we never expect/expected it to happen, so we don't have a plan for it. It'll be at our own discretion, based on the situation.
---
It looks like I got Z1mZum'd! Congrats to the greatest Guru!
SpC2k4 Triple Crown WINNER (Oracle, Betting, Spread Betting)