Office hijinks, continued

Some woman who uses the ladies' room on my floor, which is shared by several companies, has recently embarked on an interesting pattern of behavior: lining a toilet seat very neatly and very completely in paper towels, which she then leaves behind. Leaving me to have to idea whether she ever sat down on said paper towels. Clearly in either case I am not disposing of them, but she keeps doing this, in the same stall, every day. One of these days I just know I am going to have to use the bathroom, the other stalls will be taken, and then what do I do?! Ick.