Scottrade's No buy and no buy/no sell of certian companies (HRNF is on the NO BUY list) due to clearing restrictions.
I think that because HRNF has been dumping so many shares for so long, and doesn't update the markets with their new share structure (many still show 1.6 billion or so outstanding shares, it is actually closer to 3 billion shares out; the broker gets an alert on a larger percentage (of broker's outstanding share count number) of fails to deliver. Since Scotrade is a low-fee broker, I believe they don't want to risk covering the fails to deliver (have to cover them within a short time period), they put restrictions on cetain stocks.
If someone is really dumb enougfh to buy shares at these high prices, they can simply open another brokerage account with someone else. Usually some others allow you to trade these questionable diclosure companies, IMO.