Sails and wind go together, often necessarily so. How else can sailing ships actually go anywhere? There's another kind of sail that has a less obvious relationship with the wind, and you certainly wouldn't want the wind to propel that sail anywhere. How will the wind affect your new shade sail?
Some parts of Australia are far windier than others, but essentially anywhere can be exposed to considerable gusts of wind, even if this is rare. Before you invest in a new shade sail, you might be wondering whether a strong wind has the ability to detach shade sails from their moorings, or even to rip them in half.
You can rest easy because shade sails are designed with a certain amount of wind resistance in mind, and there are ways to increase this wind resistance, depending on your need (and more about that shortly). This relates to both the fabric and its anchor points. The tension of the fabric doesn't (and indeed, shouldn't) be loosened to increase wind resistance, as the generally curved edges of most shade sails are designed to allow the wind to flow over the surface of the fabric. Loosening the tension of the sail can disrupt this process, potentially damaging the overall structure as the wind pulls at the sail's anchor points.
If you're concerned about potential wind damage to your new shade sail, you can order one with a higher wind rating, meaning it can withstand greater (and more frequent) gusts of wind. However, you should also take surrounding structures into account (including your own home), as this can create shelter that will minimise the effects of the wind.
When you feel that your new shade sail needs the most possible protection against the wind (such as if you live in a part of Australia that traditionally experiences a great deal of wind), then the selection and installation of the sail should address these concerns. You should opt for a sail with perforated fabric, allowing the wind to pass through it. These perforations are tiny, and won't affect the shade's primary purpose of protecting you and your family from the effects of the sun. Additionally, the anchor points should be reinforced.
So while a certain amount of wind will already have been accounted for in the design and installation of your shade sail, there are additional ways to protect a shade sail from particularly strong winds if you feel this is a particular risk in your neck of the woods.