Driving a 2WD vehicule to Landmannalaugar - costly business?

I have read, on French forums, that some people got fined for having driven their rented 2wd car to Landmannalaugar.
In one thread, the person was told he had been fined 900 euros (!) when he brought back the car to the Hertz.

I have been informed that the rescue teams staying in Landmannalaugar, and patrolling the region, take pictures of the rental cars and send them to the car rental agency.

I'm not sure it all really legal but if you don't want to make the cost of your car rental more expensive than it already is, avoid driving on "F" roads with a 2WD.

yeah driving on F-Roads definite no no! And so it should be, the cost of a rescue mission to one of these areas is astronomical. It raises taxes for everyone and makes everyone less sympathetic. There aren't many places you can't get to by 2WD, those there are you should stop being a tight arse and pay for a tour/bus.