Evidence
Approval you can't prove is a favour you gave.
When a customer disputes extras months later, nobody re-litigates whether the work happened — they litigate whether it was agreed. Proof of approval comes down to three questions, and every kind of evidence ranks by how well it answers them. Here's the ladder, strongest to weakest.
Three questions any proof must answer Five kinds of evidence, ranked Details that decide disputes
01 — The three questions
What was agreed, when, and same words.
Any proof of approval has to establish three things: what was agreed — the actual scope and price, not the vibe; when it was agreed — before the work started, not after; and that both sides were looking at the same words when they agreed it.
Every evidence type below is really just a scorecard against those three. The reason signatures outrank texts, and texts outrank memories, is how directly they answer them.
02 — The ladder
Five kinds of proof, strongest first.
Wording, price, time impact, dated signatures from both parties. Answers all three questions completely — this is the ceiling, and nothing above it exists.
Full wording sent, unambiguous “approved, go ahead” received. Strong — though “yes” against a paragraph can invite a “I didn't read it all” later.
Photo-plus-price and a thumbs-up shows a number travelled and goodwill existed. Weak on wording — it rarely shows the scope behind the figure.
Your contemporaneous site notes help your credibility, but they're your handwriting about your recollection. Corroboration, not proof.
Two improving memories and an invoice. This isn't evidence of approval — it's a prompt to start writing things down.
03 — The details
Small fields that decide big arguments later.
Date on each signature
One date proves the order of events: agreed, then built. Approval dated after completion reads as an invoice chase, not an approval.
Both parties sign
Your signature alone records your commitment. Theirs records the agreement. One without the other is half a document.
Time recorded independently
A timestamp from the system holding the record beats a handwritten date — nobody argues with a clock they can't reach.
Stored where neither side edits
A PDF both parties keep, generated once and locked, ends the “that's not what I signed” conversation before it starts.
04 — Electronic signatures
A typed name and a tap carry real weight here.
Electronic signatures are recognised across Australia under the Electronic Transactions Act and its state equivalents — signing on a phone is signing. What gives an e-signature its strength is the same trio as everything else: it's attributable to the person, it's attached to wording they saw, and neither party can quietly alter it afterwards.
This page is general information, not legal advice. Bias declared where it always sits: ScopeLock exists to make the top rung of the ladder take sixty seconds — describe it, link them, both signatures, timestamped PDF neither side can edit. Free under A$500, whatever else runs your jobs.
Straight answers
Questions people actually ask.
Is a thumbs-up emoji an approval?
Courts and tribunals have treated emoji as capable of signalling acceptance, so it's not worthless — but it approves whatever message it sat under, which usually wasn't the full wording. Treat it as corroboration that contact happened, and get the signature against the actual document as well.
They approved verbally and now deny it. What can I do?
Rebuild the record immediately while memories are fresh: write down what was said, when and where; send a recap text stating the scope and price and ask for a one-word confirmation; gather progress photos dating the work. Then apply the ladder — the recap-with-confirmation moves you up two rungs in one message.
Does a photo of the signed paper count?
Yes — a clear photo of a completed, signed variation is accepted practice, and far better than an original that's been lost. What it loses to a proper digital record is independent metadata: anyone can argue about when a photo was taken, which is why timestamps from the tool that created the record matter.
Who should keep the copy?
Both of you. Sending the customer their own copy the moment they sign does two jobs — it proves the wording they saw, and it means their copy matches yours forever. A record only one side holds is a draft of a dispute.
The next one's coming
The next “can you just” is already on its way.
Price it on your phone, they sign on theirs, you both keep the PDF. Under A$500 it costs you nothing, ever.
No card, no trial clock. Your customer doesn't need an account.