Shield Security is a company based in Amsterdam. From securing employees to thorough business analysis, reducing risks is their specialty. It’s a booming business, yet they have one problem: to find skilled employees.

This is an example of highly targeted advertising. They’ve constructed special suitcases where a recruitment message was written in steel letters. When scanned at airports or other public locations, the working security officers could read what Shield Security had to say:
Wanted, security personnel.“.
Special promo teams, as well as the employees of Shield Security, uses these briefcases.
Genius, although I wonder whether the recruitment action had a lot of success..

UPDATE: This idea has been done before.