Queensland's guardianship legislation requires that a witness to an enduring power of attorney or advance health directive not only certify that the principal signed the document in their presence, but also that the principal appeared to have the capacity necessary to make the enduring document. This article examines how solicitors fulfil this obligation to certify the principal's capacity when witnessing these documents, drawing on empirical research and a review of publicly available court and tribunal decisions. The article concludes that the current practice of solicitors when certifying the capacity of principals to complete these documents falls short of best practice.