Avoidance tactics

My daughter has a deal with us that, if she stays dry and clean in underwear all day, she can pick a prize out of the laundry basket o' prizes. At the beginning of this agreement, we went to several stores and picked out things to put there - pretty underwear, toys, crafty things, books. If she has an accident, she immediately gets changed into diapers and we try again tomorrow.

My daughter understands this process well, since we've been doing it for about 4 weeks now. Today, I picked her up from preschool before naptime so she could nap at home. They didn't know we were changing that for July, so they put her in diapers for naptime (which I'm okay with) with underwear over them (which I don't understand, but will go along with).

After her naptime, I put her on the potty to get her to pee and to get her out of her diaper and into her underwear again. Upon pulling down her underwear, it looks like she'd pooped a very small amount in there. I questioned her about it.

Me: Claire, did you poop in your underwear at school?

Claire: No.

Me: Why is there poop in your underwear then?

Claire: It happened at school with Ms. Selena.

Me: What happened at school?

Claire: (tilts head to one side and the other, as if thinking.) I'll tell you later.

Me: (with mouth falling open) No, tell me now.

Claire: At school, somethin' happened, and I went poop in the potty! Yay! I got a sticker, but I wiped myself with three, two paper towels and pulled up my underwear. Ms. Selena helped me clean it up, so I didn't poop in my underwear, I pooped in the potty. Can I have a prize now?


Isn't she a hoot?