The government rules that everyone who wants to play a lottery has to buy the ticket before 20 December. The prize is told to be 1'000'000. After 20 December (and before the game ends) the government decides to increase the prize by 10 times the original amount, but it is too late to buy tickets now. Since the prize has been increased nobody who bought the ticket can claim to have been damaged (they have been gifted actually). But what about those who didn't buy the ticket? They would have bought the ticket if they knew the price would have become so big. Can they legitimately claim to have been damaged by the government decision to increase the prize?
(Suppose that the prize is completely irrelevant compared with the government budget so that the public finance is actually not affected)