What is the Fascination?

Ethan, aka Master 3 is finally toilet training, relax the fascination isn't with what you are thinking. When he goes to the toilet he likes to have the door open, privacy isn't something 3 year olds worry about (as demonstrated by how many visits i get while in the bathroom), the problem comes in that his little sister likes to visit him while in there. Now that would be ok if she just chatted to him or gave moral support in the toilet training endeavour, but instead she finds it a necessity to remove all the toilet paper from the roll. What is the fascination? It isn't functional on the floor , you can't really wear it, its not even colourful (I but the plain white rolls, sometimes even the unbleached) I am starting to think she does it just to get a rise out of me. Surely my little angel girl would not be so devious would she?