We used the stamp in particular on parking fines - because our team could easily access them (after all, hundreds of thousands are issued in Dubai every year).

This is as guerrilla as it gets, “abusing” official documents. We know: each stamp achieved 100% attention. We don’t know how many tickets got stamped in total. But consider this: a $40 investment in a stamp reached hundreds of people - a single sign up for an Arabic course resulted in a ROI of $2180.