Visual interference
The user expects to see information presented in a clear and predictable way on the page, but it is hidden, obscured or disguised.
Definition
There are numerous ways to interfere with the visual design of a page to hide, obscure or disguise information. Visual perception can be manipulated by using small, low contrast text. Comprehension can be manipulated by creating a chaotic or overwhelming interface. User's expectations can be violated by placing important information in styles or location they would not expect.
Example
In 2019, Tesla added an eCommerce feature to their mobile app, allowing Tesla car owners to buy upgrades for their vehicles, such as an autopilot that would unlock "Full Self-Driving" capabilities for $4,000. Some customers purchased this by mistake, and were outraged when they discovered that Tesla was refusing to provide a refund. Renowned author Nassim Nicholas Taleb complained on Twitter: _"I unintentionally hit the buy button while the app was in my pocket". _
Hidden on the purchase screen was some small, low contrast text stating "upgrades cannot be refunded". This text was the lowest contrast text on the page, and was difficult to see (Image source: Reddit, 2019).
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References
Misdirection (Brignull, 2010), False hierarchy (Gray et al., 2018), Visual interference (Mathur et al., 2019).