Pardon my newb ways, but the thing I don't get about when people do this, is that there doesn't appear to be any upside to it? The only reason I can see why you wouldn't at the bare minimum give your school half a terms notice, is that in some countries there might be a way of barring you from leaving the country as you are in breach of a contract? Or would a school try and sue you maybe to recoup recruitment costs? If you are miserable then saying to your school..... "Look this just isn't working out for 'reason x', I know this isn't ideal for you but I'm prepared to give you 6 weeks notice."...... Now you at least stand a chance of getting some kind of reference out of them? So why is this a relatively common thing?