There was an article about it a long time ago - they didn't tank it but Anderson didn't bother putting any game plans in place for the game knowing he had to play them the week after and winning the game wouldn't achieve anything for us.
Notice the following week in the semis how the defence on the edges changed in particular Reddys/Grothe side, grothe came in and reddy took the winger, it helped stopped the dragons main set play quite a few times. Don't tell me Anderson just thought of this the week after round 26.
I think the article is a myth. I remember a lot of people speculating it was the case, but I never read quote from Ando. And I question how much game planning you are going to do in round 26 anyway. Plus as I said the results of 4 other games that round, all occurring after our game, had a direct result on where we finished, so any plan on playing St George in finals was too reliant on luck to be a real plan.
Any improvement in Reddy & Grothe was probably because rather than watch Dragons' attack on video, they experienced it firsthand the week before.
The extent I think to which it was likely tanked was individual players not focused on the game (long winning streak, already made finals and all that) and no game plan was likely just 2nd half when we already down something like 3 or 4 tries. I believe the turnaround was because it was finals so players were more focused (forwards were faster at beginning of game), we had seen their game style the week before, and Dragons were probably a little lulled after winning, but I doubt extremely so that it was any great plan by Anderson.