I have recently learned the hard way to make sure scheduling policies are absolutely crystal clear before hiring on. My current job was described as "3 8 hour evenings and 2 8 hour nights a week", which sounded great, although a bit vague.
Turns out, they neglected to inform me that the 2 night shifts would be Saturday and Sunday. Every. Stinking. Week. Nor did they let me know that I would never have 2 consecutive days off (I'm off Mondays and Fridays.)
There are no concrete staffing/scheduling policies here, so nothing says they can't schedule like that, I suppose. I very politely advised Mgmt that I would finish out this schedule, as it was already posted, but was not informed that it was an every weekend position and thus did not sign on to work every weekend. After this schedule is finished, if they require someone who can work that (gawd-awful, miserable, physically exhausting, trainwreck of a) schedule and are unable to change it, I will happily go back to travelling without a backward glance.
(Sorry for the vent... This just happened to be a subject that hit a nerve!)