Was reading about this recently. Sportsbet often pay out on markets early and quite often they get it wrong with the thing they are paying out on eventually winning or not winning etc. Alot of their punters will reinvest their money like you said TBB and alot of the time give their profit back and they will often finish ahead out of it.

Sportsbet also get a heap of publicity out of it. Pretty much the whole footy world would of heard about it and people would of been scratching their heads. It generates them free publicity, new customers and plenty of traffic.

Its actually pretty genius marketing if you ask me.