Hear, hear.
To add to that, where is the life-work balance? After a run of duties like that you spend your two days off recovering and getting back onto a normal time scale, whilst totally knackered. Often the last thing you want to do is go out for the day or for a night out with friends. Or if you do you are too knackered for the next set of duties. When it is continuously like that, especially when working 6 or 7-on, 2-off it gradually gets more tiring as time goes on.