Late in a tournament, all-in play preflop is very common, especially from the medium and short-sized stacks. The reason players do this, especially late in tournaments is to steal the blinds, which can get very high relative to their chip stack.
Players who go in with the goods each time are very easy to read...when they push early in a hand...FOLD.
I understand that many players, especially in
freerolls, go all-in with a lot of garbage...call them with good
hands and you will win in the long term. Sure you might take a couple of bad beats, but long term you will win a large amount of $$$.