I feel like licensing could be an issue, but if you're advertising that you will lose someone's money, either you succeed (hard to argue that the customer didn't get exactly what they asked for), or you fail (hard to prove damages).
Advising on losing stocks is definitely an investment advice, it just means client will short them. This will be obvious to a court especially if the advice is for money. They will not bite for the absurd argument of paying for losing money.
