One thing though is that no one is 100% sure on any stock. I used to hate Cramer back when people thought he was the best thing to ever hit the market. My stock would go down 10% one day with no news at all except for Cramer saying he doesnt like it. Now, not too many people buy or sell based on what he says nearly as much as when the show just started getting popular. He is an entertainer first and then a stock analysis second. He gets more money from that show than he does with his stocks.
Oh yeah, I dont know about other brokers but Fidelity has had a rule for quite some time that you cant short a stock without having at least one million dollars in your account. Its too risky since you could easily lose it all and more on top of that and they dont know if they will see that money.