NO! a reliable broker/or house, will only alow shorting on shares that they have certs on, and only one short per cert!
using scottrade, I have shorted There were times I wanted to short a stock and they turned me down because they had no shares to short! ON the same stock!
What it does is put the broker/house on the hook for the stock, and that is why they have what is called a margin call!
and if you think the IRS can be A ho le s, try to say catch you next mo to a broker!