Ok, so basically the same as if you had a mag stripe transaction in the US where you weren't required to sign (like for a small $ amount; the exact number seems to vary by location). No harm to the cardholder, all of the risk is back on the vendor due to a lack of training on the part of staff at that location. Probably not a surprise since these cards don't appear to be very common yet.

Perhaps when people get a new card, they should be given a stack of pamphlets to hand out to storeowners to make them aware of how the transactions are supposed to work.