If she only has an accident if she "doesn't want" to go potty...then don't let her have the option! We've always told the boys that "everyone goes potty before bed" so it's a normal part of their routine. When the youngest (BRAND newly trained) doesn't want to...we simply tell him that we all have to do things we don't always want, but potty before bed isn't an option.
You can also just let her go to bed without the pullup (with the mattress protected!!!) and see if she wakes when she gets wet.
My boys stopped peeing over night before we really started training, so I'm not even sure they would wake up if they did have to go! We help control it by limiting drinks to nothing after supper and peeing before they go to bed (and first thing when they wake in the morning)
at 5:24 AM on Jan. 27, 2009