People who call their children by their middle names really need to think this thing through. 
OK, I must comment on the middle name thing. When I taught elementary school, I encountered this a few times--at least once a year--always right AFTER I labeled everything in the classroom (name tags, cubbies, workbooks, my grading roster, job charts, birthday chart, you get it EVERYTHING). Then the parent would come in and announce, "He/She goes by his/her middle name." *Sinks down*

: Now I had to relabel everything -- which can take more time than you expect, because you have to reprint lables, remember what font/size you used, get an extra name tag, cut out the extra birthday balloon, all that jazz. A few times I got a heads up from the previous teacher, but I opened two new schools (so that didn't apply) and new students (didn't apply) or one thing or another so I wasn't always forewarned.
I vowed NEVER to do this with my own children. Can you see the set up coming here?
Then I had my daughter. I always knew she would be named Elizabeth after my grandmother, plus I loved the name. My husband and I tossed around a few middle names, and finally fell in love with Nicole. He didn't want to call our daughter Elizabeth, wanted her to go by Nicole. Not a problem, except Elizabeth Nicole sounded better than Nicole Elizabeth to us. We ended up naming her Elizabeth Nicole and calling her Nicole. AGH! I did exactly what I vowed never to do. But, when she started preschool and elementary school, I made it very clear (even left notes for teachers before the school year) that she goes by Nicole. I hope I can prevent extra work on the teacher's part.
So Pickles, Lill, Kay, I'm guilty as charged! And yes, it does make things a bit more complicated.
Funny side note, my husband's brother goes by his middle name, and my husband used to comment on how much of a mess that was for his brother growing up. LOL. Then he turned around and did the same thing.
Sorry to hijack your thread.