Now that I think about it, Im not sure if you have to pay short interest. because you open a new position.
Apparently different brokers are now doing different actions. Seems because the stock of short stock availability is low on CCME, and there are many naked puts written, so buyers of puts must for example though IB not be able to auto-exercise or use buil-in exercise option, but must actually message IB explcitly through message center what to do. This is gonna be messy.