What happens if your shares are already loaned "short"? Can you still put a GTC sell order in???? LOL. I don't think this trick does anything. When the California and Connecticut teachers start dumping their stock, prices will go down and shorts will make money. If you want to protect the stock price, put GTC "buy" orders in right at current market price ;)
Actually, if your shares were already lent to a short then placing a high priced GTC order would potentially have even greater effect. Since placing the GTC order on your shares would then force your broker to either find other available shares to lend. If he can't find enough then he would call in the short and force him to cover.
The teachers don't own the stock directly, they own it through funds. The funds, for the most part, are rejecting the notion of managing their portfolios based upon the social concerns of the pension funds.
You really think that you can be prevented from putting a gtc sell order in for YOUR OWN stock, based upon your broker having lent it out? They would probably have to look for another batch of shares that is less risky (due to no gtc to sell at high level order). The trick works best if you do it right after you purchase the shares, which is what I always do.
Another reason to prevent your shares from being lent is tax related. If a dividend is paid while your shares are lent, the dividend will not be a "qualified" dividend and will be taxed at your full rate, not 15% as now. (although, TD Ameritrade now will pay an add-on amount to the dividend to compensate for the higher tax if they lent the shares)
Placing a limit GTC limit order will prevent the shares from being lent. But specify a limit very much higher than 60 and then closely monitor prices to further increase the limit if price rises substantially. As large as the short position is here, if a miracle happens and a squeeze begins, this thing could rival the Porsche/VW squeeze