Back when I was a broker (pre-civil war), your sister would have qualified as what we called a "mullet indicator." All the brokers in the office kept track of a handful of customers who over the years had proven themselves incapable of making a correct decision on their investments - they always bought at market highs and sold at bottoms, bought the wrong groups, and chased every fad or story stock too late.
I suspect that most every large brokerage office still has a similar group of customers that they watch.