It also says to check with your surgeon, and I'd do so - and then take their word as gospel. Some techniques have a higher risk of prolapse than others, and some people's anatomy is more at risk than others'. I'd personally say the guide is being extra cautious, and that while this is technically possible, it's not a significant concern for anyone who did consult their surgeon.
(Suzi, I wonder if that's b/c Rumer is still fairly new, with a relatively small number of patients? I'd guess the chances of *all* complications occurring goes up as the total pool of patients does, just as a statistical thing. Of course, the other way it could be true is that she automatically assumes anyone with a prolapse didn't follow the dilation rules...)