I have been watching with interest the tour of Spain. In this race and the TDF I've noticed that there will be a few riders break away early from the pack and ride to exhaustion. In my limited experience they have always been caught by the pack well before the end of the race and they fade rapidly to the rear. From a team standpoint, what is the purpose/advantage of such a move? It seems that the team just looses one of their good sprinters or hill climbers. Any comments?