Karnataka exit polls

The 3 phase elections are over in Karnataka and the results are going to be announced in less than 48 hours. The exit polls done by different news agencies throw a different picture altogether. Altogether they are making bluff of the results, how can they decide the fate of all the constituencies just by asking questions to few people that too not covering all the constituencies. These exit polls are done to increase the TRP values of the news channel and nothing else.