Can bounties offered by me can turn out to be disadvantageous for me?
All bounties are paid for up front and non-refundable under any circumstances.
If your new reputation brings you below the requirement for any privileges, you will lose access to those privileges.
You may not cancel a bounty once it has been started.
The utility of bounties on martial arts for question visibility is very low. The volume of questions on martial arts is low enough that most everyone will see any question you post.