Agreed, never understood the limitations and restrictions myself. Other than of course the limitless risk of infinite loss. You hit on a unknown factor to most OTC traders.. Premiums... There are premiums also associated with shorting a stock, so not only maintenance margin requirements and regular account margin but also premiums to pay to borrow. Oh did we forget interest in some cases?
Going short is more problematic than any other trade out there, options have become the choice for most now.