I just called a brokerage house about this and found out that even though many Venture stocks are not marginable, if they are held in a margin account, the brokerage CAN short these stocks and use your holdings. But, you can call and request that your stock not be used for this purpose (hyphothacation, might have the spelling wrong). I don't know if it works the same with Canadian firms. And of course, this will not stop naked shorts, as they aren't borrowing anything.

C