Residents must not be scheduled for more than six consecutive nights of night float.
[The maximum number of consecutive weeks of night float, and maximum number of months of night float per year may be further specified by the Review Committee.]
No. As long as you get every 7th day off, the program is fine. A lot of us have done 4-6 weeks of night float in a row, only having eg every Saturday night off. It's actually better to have it all in a block than spread out so you don't have to keep switching your sleep cycles.
We did 7-8 weeks in a row in my program as that's how long our rotations were. And some people (after rotations were adjusted to accommodate new rules) did back to back night float rotations too (total about 12 weeks in a row, give or take). Some people preferred to 'flip' their schedules only once. And night float was a rotation where vacations were not allowed.
But the rule posted above is the only one I'm aware of: can't do more than 6 days in a row on nights. But as L2D states, you get Sat or Sun off and then can do another 6 days in a row.