They can run, but they can't hide. They'll get theirs just like every other parasitic class has in the past.
How naively optimistic of you. If history teaches us something, it's that most parasites get away with their misdeeds and live happily ever after. A few chopped heads might make you feel better, but doesn't change the big picture.
Last I checked feudalism is more or less nonexistent in 2015, as is slavery and other classical forms of exploitative class society, so I'd argue that history teaches us otherwise.
Most of the heirs of feudal lords and slaveowners are now part of the "capitalist class", you know? The system did change, but the people who benefited from it didn't suffer that heavily.
Old upper class families only last for so long. Most of the nobility are ordinary middle class today.
However- rather disturbingly - in England studies show that the rich today are much more likely to be descended from the Norman elite of The Doomsday Book than the peasantry. Despite nearly a millennium of social change, unrest and widespread education, you still are far likelier to go to Oxbridge and be in the Civil Service if your family has Normam heritage.
William the Conquerer has a lot to answer for.
Oxbridge and Civil Service only makes you upper middle class, not upper class.