There is no need to actually prosecute the passengers, just impound the offending item for longer (and with greater risk of pilferage) than it would take to get the item if left behind.
It also does not have to be perfect in all countries as long as most do so the norm mindset becomes better to leave it than risk the consequences.
Also my prior suggestion of cash reward for leaving items would probably be more effective if instead it was 1-3 years 'gold/platinum/rubidium' (whatever is hardest to attain) status in the airlines mileage program. To many business travelers that would be much more compelling than $100.