A notarial act is a statement by the notary about what happened in front of them. Part of that statement is implicit: that the person signing understood what they were signing and chose to sign it. If either of those is untrue, the act is worthless — and worse, it lends the authority of the office to something that should never have been executed.
So a notary is not simply a witness with a seal. Every appointment involves a quiet assessment that most clients never notice, and occasionally an appointment that does not proceed.
Capacity asks whether the signatory understands the nature and effect of the document. Not whether they are clever, not whether the transaction is wise — whether they grasp what this particular document does.
Free will asks whether the decision is their own. A person can have perfect capacity and still be signing because someone in the next room made clear what happens if they do not.
These are separate. A notary who satisfies themselves on one has not satisfied themselves on the other.
There is no test a notary administers. What happens instead is conversation, and the conversation is doing work.
A notary will typically ask the signatory to explain, in their own words, what the document is and what they expect it to achieve. Reciting the title is not enough. Someone signing a power of attorney should be able to say, roughly, that they are letting a named person act for them, in what areas, and from when.
Other things a notary watches for:
Capacity is decision-specific and can fluctuate. A person may lack capacity to grant a wide-ranging power of attorney but retain it comfortably for a simple consent form. A person unwell in the morning may be clear by afternoon. A notary who forms a doubt is entitled to postpone rather than refuse outright, and often should.
Where the document is significant and doubt is genuine, the usual course is to ask for a medical opinion on capacity from a treating doctor or a specialist, given close in time to the signing. A notary is not a clinician and should not pretend to be.
Duress is rarely dramatic. The signs are usually structural.
The most common is the accompanying person who answers for the signatory, translates selectively, holds the documents, or explains what the signatory "wants". A notary will normally ask that person to wait outside. Refusal to leave the room is itself informative.
Others worth naming:
None of these is proof. Families help each other with paperwork constantly and most of it is entirely proper. What they do is trigger a closer look.
Where the document is significant, a notary will often insist on a period alone with the signatory. This is the single most useful protection available, because almost everything that is wrong becomes visible once the interested party is out of the room.
The same logic governs interpreters. Where the signatory does not read the language of the document, or does not share a language with the notary, the interpreter must be independent — not the relative who benefits, and not the person who booked the appointment.
The options are broader than "proceed" or "refuse":
A notary keeps a permanent register of their acts, and in a marginal matter the notary's contemporaneous file note — who was present, what was asked, what was answered — may be the only record that exists if the document is challenged years later. Good notaries write these notes at the time, not afterwards.
Can a notary refuse even though I am paying them? Yes. A notary's duty runs to the integrity of the act, not to the client who booked it. Payment does not create an entitlement to be notarised.
Does a medical certificate guarantee the notary will proceed? No. It is evidence the notary weighs, not a decision the notary is bound by. The notary must be personally satisfied.
Is capacity assessed against the document or the person generally? Against the document. The question is always capacity to do this specific thing.
My relative wants to sit with me for support. Is that a problem? Usually not, and a notary may allow it for part of the appointment. Expect to be seen alone for at least part of it, particularly where the relative benefits.
What happens if the notary declines? Nothing is lodged and nothing is recorded as executed. You may be given reasons and a path forward — independent advice, a medical opinion, a different interpreter. Ask.