Dee-M-See,
That's a bit harsh. Wiggins was at burn out by the time it came to performing in the madison in 2008, they just didn't realise it until afterwards by their own admission.
As for the second time, it was the fault of the peloton not Wiggins. The whole of Team GB rode their guts out that day but none of the other teams were willing to take their turn in setting the pace and were happy to destroy their own chances of winning anything just to see Cav fail.
Cav was more than happy when they(Team GB and Wiggins) took him to World Championship glory in 2011 and when Brad gave him the lead out on the Champs for his 4th consecutive first place finish this year. All of them know it's a team sport, none more than Cav who relies on the train and a lead out man to get him into the right spot for the sprint finish.