You’re browsing a major online marketplace for a warm winter jacket, when a sponsored listing catches your eye: a black, fleece-lined jacket, prominently priced for sale from A$18.99 each. It’s just what you want. So you click through, ready to grab a bargain.

But when you land on the page, then select a jacket from the drop down menu, the price instantly jumps to $39.99.

It turns out the $18.99 was actually for a different product – a waterproof storage bag – which was inexplicably listed along with three variants of the jacket.

This is a common strategy used by online sellers. The platform’s search algorithm displays the headline image of the jacket, but pairs it with a more attractive price of a different product.

Frustrated? You’re not alone. Across online forums such as Reddit, or deal-hunting sites such as OzBargain, shoppers have long warned others about this type of “multi-variation listing” on popular shopping websites and apps.

It’s not just wasting your time: it can be illegal.

This kind of visual bait-and-switch trick could potentially be misleading conduct under Australian Consumer Law. It may also breach the prohibition on “bait advertising”, applying to ads that promote “sale” prices on products that aren’t available, or available only in very limited quantities.

And a proposed prohibition on unfair trading practices, now before parliament, could soon give Australians even more power to complain.

Why visual tricks like these work

Academic research helps explain why this kind of design is so effective, and also such a problem.

When a price claim and a product image are presented in close proximity, consumers naturally assume that the price applies to the pictured product.

It is a “visual superiority effect” in advertising. Research has shown that visual superiority effect means consumers process images faster and more automatically than text.

When visual and textual elements conflict, consumers rely more heavily on the visual content in forming their judgements, and form less critical thoughts when it comes to the text, such as a product description.

Consumer watchdogs have warned this kind of design tactic is a type of “dark pattern”: tactics used to nudge, manipulate or trick you into spending more money than you’d planned, or provide personal data that’s not needed.

Research has shown nearly all consumers are susceptible to these manipulative tricks under the right conditions.

Is this actually misleading under Australian law?

Let’s go back to the example of the black winter jacket you clicked on thinking it was available from $18.99, only to discover that price was for a different product.

Is this visual bait-and-switch – where a lower price has been paired with a product image it does not apply to – misleading under Australian consumer law?

Yes, it probably is.

Retailers should be warned. The national consumer watchdog, the Australian Competition and Consumer Commission (ACCC), can prosecute for misleading people with eye-catching headline claims, if those are not true once you look more closely at the detail.

For instance, just over a decade ago the ACCC pursued TPG Internet in court over misleading ads, which led to a $2 million penalty. The ads had prominent headlines about attractive internet prices – with much less prominent terms qualifying the offer.

It went all the way to the High Court, which ruled that if consumers were drawn into what the judges called “the marketing web” by a misleading “dominant message”, it could be enough to be misleading under the Trade Practices Act.

Not all seemingly deceptive ads will necessarily fall within the category of misleading conduct. It can be harder to prove if the qualification to the images or pricing is revealed before the consumer adds the product to their basket.

But Australia’s laws look set to become a bit clearer on this front.

New legislation currently before federal parliament would introduce a prohibition on unfair trading practices that manipulate consumers, or “unreasonably distort” the environment in which a decision is being made to the detriment of the consumer.

That new prohibition is intended to capture “dark pattern” tactics that are “nudging or pressuring consumers into unintended actions”.

How consumer backlash and complaints can help

Research shows that when shoppers feel they have been intentionally misled, the damage to the brand’s reputation can be severe and immediate.

Price confusion doesn’t just cause frustration; it triggers a deep sense of unfairness. That unfairness can translate into action: consumers abandoning their carts, switching to competitors, and complaining to family and friends.

If you come across shopping platforms where there are consistent, manipulative bait-and-switch tactics like this being used, it may be worth asking: is it time to shop somewhere else?

Or, if you’re annoyed enough to take action, take a screenshot and contact the business.

If they don’t stop bait-and-switch sales listings, anyone can make a report to the ACCC about a false or misleading claim. Reports from customers help inform the ACCC’s education, compliance and enforcement work.

The ACCC has named misleading and manipulative pricing practices among its enforcement priorities for this financial year. Anyone selling to Australian customers should be on notice.

Jeannie Marie Paterson has previously received funding from the Australian Research Council for a project on misleading conduct.

Adrian R. Camilleri and Jessica Pallant do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.