Talking of shorting... In the U.S. there are about 4.6 million shares of AT that are currently being shorted. I don't have access to a Bloomberg terminal, so I don't know the number for the Canadian market. Anyone?
It is difficult for the average retail client to be short. Brokerage firms tend to lend to those clients that do the most business with them (institutional traders). There is a cost to borrow a stock, and it is a profit center for brokerage firms, when they lend out the stock.
My general rule of thumb is that the "shorts" are usually smarter, and they tend to win. They do their research, and look for weakness in the herd of stocks. Whether you like it or not, there is nothing that you can do about it. (Disclaimer: I don't generally short stocks, and the few times I have, it was because I was trying to lock in a profit on a convertible instrument, that I owned, so I wasn't really short, in my mind.)
Have a good weekend.