This is Sascha Reichert and guess who he got this sticker from? I've finally found a source to produce more stickers at a reasonabe price and have ordered some two days ago. I've been running out of stickers and had to deal them out very parsimoneously.
The video seems to be about the "Always wear your helmet tour" (I can't get sound here so I can't really enjoy it fully). There is an even older initiative in this direction by Chris Eggers, w-y-h.org, Wear Your Helmet. It was started under the impression of a skater having died skating the new skate park in Hard, Austria without a helmet.