"But how do we have to play against these types of 'players' "

To be honest it's a multiple answer question.

1) If it just happens out of the blue - there is nothing you can do about it. I hate to say it, but that's poker

2) If someone is continually raising with junk - wait and pick your moment when you have AA or KK and then let the gods of odds help you out. If you don't want to risk your tounament place in a race, then fold and wait till you have enough chips off other people to do it.

3) If someone is always chasing gutshots and the likes, make them pay. Again, if it's your tournament at stake, let someone else take the risk and collect your chips from other players, and come back to fight when you are well ahead.

The worst possible thing to do is react purely for the sake of reaction.

I know there are times when you just don't know the guy is a dick, and he calls your trips with a gutshot and hits. But that's life, and you will win if you keep doing it.

I often get sat (online and offline) next to a maniac (read idiot). I had one on my left (online) the other day and every single hand (almost), no matter what I did he'd raise it about two or four fold. It got to the point it was really pissing me off and I nearly reacted by calling, but I didn't. I just kept on folding until I had KK in my hand, and enough chips to survive the battle if he sucked out. He pushed all-in and he was gone. On other occasions I just bite my lip and wait for someone else to get fedup and take them out.

Rambling off topic a bit now, but back to the main subject. What can you do? not a lot :-p