My intelligence test for cashiers: arrange cans into a rectangle (3 x 4).
Cashier counts cans one by one. IQ = less than 100
Cashier counts cans by twos or threes: IQ =100-120
Cashier multiplies three by four: IQ = 120-150
Cashier looks at rectangle and thinks "12": IQ = GENIUS
Of course, this is on the Cashier IQ scale. The General IQ scale is calibrated much higher. Scores may depend on how much sleep, coffee, etc. cashier gets.
I wonder how many people on Monday morning will, for the first time, decide it is worthwhile looking through the phone system's User Guide. Personally, I like the idea of reprogramming the system so my extension gives a permanent busy signal. However, I am sure Wally beat me to it.