Many people provide gifts at various times in their lives without necessarily knowing, and generally without evidence. This could attract a dispute in which a gift could be mistakenly intended to be a borrowing. This risk can be easily be refuted with an executed Deed of Gift.
Likewise beneficiaries of a discretionary trust may not seek to receive unpaid present entitlements but over time seek to reclaim against the trustee. It is important for the Trustee to put in place a Deed of Gift to cover that consequence.