I don't know how this had resolved itself last year, but somehow it wasn't a problem then. She was toilet trained by about March, so she'd clearly spent about three months using the bathroom, or being allowed refuse to use it, in her old classroom without incident. In September, though, - new classroom, new teachers, new people to inculcate in the ways of Mabel; or vice versa.
Mabel and I spent a fraught few mornings before she'd agree to darken the door of the classroom working out some sort of compromise whereby I would tell the teachers that she would go if she needed to, and they wouldn't make her. They agreed, but tried to make her anyway. She refused. Stalemate was reached, but they gradually realised that, like her brother before her, she has a bladder of steel and doesn't need to go all morning.
Meanwhile, though, I thought we should tackle the pants-round-ankles business as soon as possible, and the most direct method seemed to be some form of bribery. A star chart might do the trick, I thought. So I drew a few lines on a piece of paper. While I was at it, I thought I'd add a column for cleaning up, and of course there'd have to be a complementary chart for Dash too, because heaven forefend she have even the prospect of some new thing if he didn't too. Casting about for something to fill the other side of Dash's chart with, I decided maybe he could do some reading practice.
As you can see, the toilet practice was a total success. In fact, after about three days she was happily keeping her knees together (such a lady) and her shoes on, which I'm very pleased about even if she never actually uses these new abilities in school. With winter approaching, it's a good thing in general.
Dash's reading practice also went really well - I told him ten minutes' reading was enough to get a star, and he was totally motivated to pick up a book any time I could sit down with him. Sadly, once those stars were filled in the habit didn't persist, but maybe I can start another one for something else. When he'd finished with the reading stars he started trying to earn clean-up stars as fast as he could, only just stopping short of making a mess in order to be rewarded for cleaning it up. (No need for that. There's always a mess around thanks to his sister's habit of playing with a small subsection of every different thing at once. Though I did have to stop him from cleaning up when she was still in the middle of playing.)
So, on Sunday, the chart reached the dizzying heights you see in the picture, with all of Dash's stars filled in. (Please excuse the crumple marks. Mabel was making her displeasure known one day.) I knew we were in for trouble. Dash spent all morning mooning around asking when we'd be going to Target to buy his new thing. Mabel spent all morning telling me earnestly how it wasn't fair if Dash got a new thing and she didn't. Pointing out that when (when? if ever?) she fills in her side of the chart, she'll get a new thing and he won't, did nothing for me. We did not go en famille to Target for the purchasing of the object; I sent Dash with his father and instructed them to pick up a small item from the $1 section to appease The Unappeasable One.
Dash came home with not a light saber, not a watch, and not shoes, but a new Nerf gun (oh joy); and they brought Mabel a tube of glow bracelets, which kept her happily entranced all afternoon.
So that worked out better than expected. Next chart: back to eating vegetables, perhaps.