Naked shorting is illegal no matter how you slice it. If the shares are unavailable to short a broker can't "legally" allow a security to be shorted. They get caught in the act when they thing shares will become available in a few days so they can cover their tracks. The shares have to be available to borrow before you can legally short them.
I'm not sure what you define as abusive.
"Naked shorting is the illegal practice of short selling shares that have not been affirmatively determined to exist."
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