Since Sulax brought it up, what JG must've been referring to was to keep one's shares in a cash account at one's brokerage firm. Securities in a cash account are not allowed to be lent out by a brokerage firm. If one's securities are held in a margin account however, the firm can lend out your shares without being required to notify you. Further, you are exposed to the re-hypothecation risk that your brokerage firm might bestow upon you, if things get out of control for them.
For those CRGS shareholders who have a margin account and never use their margin, they may want to call their broker and change their account status to a cash account. Minimal paperwork is involved. This can help put further pressure on a structural short position.