"Nifty vanity plate," said Officer Jane Curtis, approaching the driver's side of a red sports car that she'd just pulled over. "What made you choose that?" she asked, as she kept one hand poised over her stun gun.

"It's not a vanity plate," said the confused driver. Officer Curtis quickly determined him to be much older and more feeble than she had anticipated. She relaxed, warned the man about his speed, and left the scene.

Here are the six letters as they appeared on the man's license plate. Can you figure out why Officer Curtis thought it was a vanity plate, and why it made her nervous?

N A C  L 9 V

Here is the SOLUTION.

THE SOLUTION:

She thought the sequence - NACL9V - was a clever abbreviation for "Assault & Battery."

NaCl is the formula for sodium chloride (table salt), while 9V is nine-volt, a common household battery.