This is how Sky (at least for eight years or so) lost the 2011 Vuelta: because Chris Froome was such an unproven commodity, when he surprisingly found himself in red after the TT, they chose to use him as a domestique to the more proven Wiggins regardless, because Froome had seldom shown more than a couple of consecutive good days before, so they didn't trust him not to fall apart later. As a result, he was taking pulls in red on La Manzaneda - an otherwise somewhat unthreatening mountain, especially compared to San Lorenzo or Angliru - and time lost on that stage as a result wound up costing them the GC - until of course years down the line Cobo got scrubbed.
For me, them letting the others attack and hopefully defeat Sepp is the only thing Jumbo have going for them.