LOL IB?? no one would pay $2.50 per share to short a penny stock. those borrowed shares aren't free- but most retail folks don't know much about it. go read IB's FAQ its plain as day
retail shorting is for big boards- on margin, lots of liquidity and playing put / call spreads.
only retail idiots try to short OTC.
MMs are the exception they can NSS all day long and get away with it.