Ouch, I never had any of those types of rosters. My days off were mostly either 3/4 days. Had the very occasional 2 day block of days off but looking back at my rosters the days before always finished on an early allowing me to get back home in the evening. Four day blocks were certainly not the exception for me and they'd occasionally randomly roster me a five day+ block of days off.
For example In July last year I GDO'd two days and they wrapped another five around them giving me seven, in the middle of summer! It's amazing that experiences can be so different. I think it was possibly as a result of being a contractor on the top rate that I worked less than the SO's who didn't get any sector pay.
If it had carried on like that I wouldn't have left, as it was almost a cushy number (or as close to one as you will get nowadays). However I knew as soon as I went permanent that particular set of circumstances would have gone out the window.