There’s a joke in Israel that goes like this: A customer at a restaurant discovers a NIS 20 charge on his bill for something called the “works.” He doesn’t recall ordering anything like that and beckons the waiter. "What's that for?" he asks. The waiter shrugs. "Nothing. Sometimes it works and sometimes it doesn’t.”

Whatever you think of the joke, it is said to have spawned the popular Hebrew slang expression “shitat matzliach,” literally “successful method”, or as the British say, "trying it on."

Generally used in a pejorative sense, shitat matzliach describes a deliberate attempt to exploit another person's inattentiveness, assuming there will be little, if any, penalty for getting caught. It’s a kind of “if-it-works” gambit – as in “If it works, it works; if it doesn’t, it doesn’t.” For victims it boils down to “caveat emptor,” “buyer beware.”

The expression may not apply at the flea market, where everyone expects the vendor to kick off the haggling with a ridiculously high quote – that is, as long as the vendor totals up the purchase correctly at the end.

But lately, it has been increasingly used in reference to the alleged business practice of regularly overcharging unsuspecting customers for goods or services. A proposed amendment to the Consumer Protection Law making its way through Knesset would require businesses to refund customers NIS 16 for any unsubstantiated charge. It is hoped that this will eliminate the low-stakes conditions that might be encouraging businesses to try the gambit.