T-Shirts with sun alert

Situation: It’s time for open air festivals: every year, cheerful vibes, good music, and sunshine allow everyone to forget their worries – and their sun blocker. How do we make the visitors of open air festivals in Switzerland aware of the importance of UV protection – before the sunburn?
Idea: The idea is to distribute T-Shirts with a built in sun alert. This alert is triggered as soon as the T-Shirt is exposed to UV rays. Thereby the persons wearing the T-Shirts and the people around them are alerted - early enough, and in a surprising manner.
Execution: The secret is UV-sensitive paint: the invisible “Sun alert” imprint on the T-Shirts turns red instantly as soon as it is touched by sunlight. The importance of early sun protection becomes obvious. If the sunlight is really intensive, the imprint appears in a burning lobster-red. It fades with decreasing UV intensity, and completely disappears when there is no UV light. Promoters distributed the T-Shirts together with Sun Look sun blocker samples to festival visitors.
Result: The promotion attracted attention and was not only a topic for conversation, but also gave opportunity for some flirting. The T-Shirts were very popular at open air festivals and out of stock in the shortest amount of time.