Murphy's Laws of school book fairs

1. First sale of the day - an 80 cent pencil - will inevitably be countered by a crisp $50 note.

2. If you put a signature on the item's price sticker at a school book fair, in an attempt to prevent shoplifting, the child will inevitably have a single ten cent coin to pay for a $10 item. Or even a $25 item. (These kids have expensive tastes. And a totally unrealistic idea of the value of money. They also believe that if you keep buying items that give you change, you'll never run out of money.)

3. If a student hands you a bunch of 16 shiny $1 coins, and it looks like he raided Mum's money box, he probably did. (And why was he so desperate to purchase a personal burglar alarm, anyway?)

4. If someone sees you sneaking a look at the EFTPOS machine manual, they'll suddenly demand you test it out on their card. Dammit. ("Go use the Ready Teller across the road please, these instructions are too obscure, okay?")

5. Of course, you're supposed to charge up the EFTPOS machine the night before. (Thanks for not telling me, Book Fair company.)

6. Stationery is still way more exciting than books, even on Day 3 of a Book Fair.

7. Tired teachers only make addition errors in front of the parents, not little students, who wouldn't notice anyway.

8. Today's grandparents are younger than most of the teachers. (Welcome to the middle ages.) But they are quite generous (Ka-ching! Ka-ching! - sound of cash register).

9. A major computer system changeover shall occur on the same day as the takings of the annual Book Fair must be finalised. It will also be the last day of term, and only one day before a public holiday.

10. The final tearful request for a $1 scented eraser will be announced precisely ten minutes after the van, full of all the cabinets of product, leaves the school grounds. (A prediction: just you see if I'm right.)