Given that Melbourne finished in the finals last year and were widely tipped to challenge for the flag this year (as well as their repeated 'yo-yoing' between top and bottom) I would say that there is more evidence of Melbourne tanking the season than Carlton. At least Carlton have been consistent in being a crap side over the last 5 years.
Get real. We were smashed by injuries. Once we were 0-9 it would have been dead easy for us to "convincingly" snare a PP, but instead we kept trying to win with half a fit squad and managed to.