I've been told that wealthy people place two liens on their own property, together equalling 100% of the value, to protect it should someone else want to place a lien on it. Is this correct? And how do we go about doing this?

You can not place a lien on your own property. If your property is owned by a LLC or Corporation, you may have another company that has a mortgage on it.

But if you could even legally place a lien on your own property, it would not protect you from a judgement since the lien is value, so they would merely get the lien given to them by the court.