Reply To: What is the issur in flying on shabbos

As by closing a door and a deer gets caught, when done to protect the house it is not a pesik reishe.
The Rashba explains that if only an issur happens then even if not mechaven for it is a pesik reishe but if a heter can also happen and you are mechaven for the heter then if the issur happens it is not a pesik reishe.