It defers to a repealed 97/7/EC, replaced by 2011/83/EU:
> Durable media should enable the consumer to store the information for as long as it is necessary for him to protect his interests stemming from his relationship with the trader. Such media should include in particular paper, USB sticks, CD-ROMs, DVDs, memory cards or the hard disks of computers as well as e-mails.
USB sticks are on the list, but so is paper and e-mail. This USB stick could have been an e-mail.
Putting aside the fact that the conclusion of this text is not at all what GP said... You do realize that this is not a law, not even a court decision, but that it is a prosecutor's opinion / suggestion to the court??
Yes, if two people are going to answer with the exact same link and nothing else, I'm going to answer both with the exact same comment.