Nosy

A colleague of mine came into my office moments ago with an attendance sheet in hand (I work at a high school). She opened our dialogue by saying "I don't want to seem nosy, but...". She directed my attention to one of my students who was marked absent on said sheet. In our school, if a student is absent, he/she may not participate in extracurricular activities for that day. In my particular activity, an absence could result in that entire activity shutting down for an evening. This student has no replacement or back up to fill in for him. There are 8 students who can't be replaced at this point.

Now, I have known this teacher for almost a year now and she has been incredibly supportive of the extracurricular activities I loom over. I believe she wants only the best for the school and her intent in showing me the attendance sheet was to help put out a fire (The student was tardy - fire extinguished). The paranoid part of me believed, from the moment she said the word nosy, that she was indeed being nosy! If she had wanted to be anything but, she would have sat back and let me check attendance for my activities students. There are over 80 students involved in my activity. Why is a teacher from outside of my department scanning the attendance sheet looking for these names?

In my heart of hearts, I know she was looking for one of the 8 names just in case. She's watching my back. But I don't want my back watched in this case. Am I out of line?