On the 17th of September 2014, a large HYP holder got his HYP stolen - his HYP where on several wallets so he was not particularly targeted, he just happend to succumb to a social engineering attack (click on a link in an email) and to use Windows (not sure that Mac or Linux would have help).
This means two things:
First, HYP-seeking robber script do exist. Second, you should take precautionnary measure to protect your HYP. Since HYP requires a running wallet to take advantage of staking, this means you cannot just lock it, you must also use the Unlock for mint feature.