I think the main problem reference the clowns post is as follows.
The problem with low cost airlines in general and this does not single out Jet2, is that if the new EU travel conditions state next available it does not mean on the same carrier.
The way l see it and l may well be incorrect, is you get put on a flight that gets you to your destination ASAP, it might mean flying by BA or who ever and might also mean a change on the way, for say via T5 at LHR.
The problem at the moment is that over 90% of all airlines seem to ignore the law and try and get away with it and are hoping that the individual gives up and does not take them to court.
This only my opinion but the Consumer Association has over the last few years also pointed out that airlines try and hide their responsibility to the travelling public behind the complex legislation.