The Toilet Paper Caper

I have been quandering a strange occurance in my home the last few months, that I haven't been able to figure out. Every time I go to the washroom the toilet paper holder is empty and the cardboard roll is there in the roller. I live in a household of 6 and if I don't change the roll no one will actually will do it. I can't figure out why, it's really not that difficult to change. One week I actually didn't do the change and after a few days there were 2 empty rolls on top of the roller just stacking up. I gave up and changed it and just except it as my responsibility to do now.